Well, after creating two successful teams on PO which got me to the teen ranks in the Dream World tier, I wanted to challenge myself and make a hail stall team. After lots of trial and error, this team is sitting at rank 34 on the Smogon server Dream World tier as I type this, which I'm pretty proud of. Hail, although it is my favorite weather condition, is probably the least useful weather condition to base your team around this generation, as you get no real boost to defense, offense, or anything like that. The advantages however are that less pokemon are immune to it, making it easier to stall and wear down teams, and Blizzard's accuracy increases to 100% as well of course. Anyway, without further ado, lets get started.
Abomasnow @ Choice Scarf
Hasty Nature
Ability: Snow Warning
16 Atk / 252 SAtk / 240 Spd
~Earthquake
~Giga Drain
~Blizzard
~Hidden Power Fire
Choice Scarfer #1. Although I usually don't lead with Abomasnow unless its against something like Politoed or Swampert leads, he usually comes in once something on the team dies just to get Hail going and to revenge kill. EQ is there for fire types like Heatran, Ninetales, Infernape, and Chandelure without a scarf. STAB Blizzard wrecks prominent threats to my team such as Gliscor, Landorus, Zapdos, Thundurus, Garchomp, etc. I chose Giga Drain over Wood Hammer for the sole purpose of surviving longer. Not to mention, I can invest more in Special attack to power up my main STAB move, Blizzard. HP Fire is there to hit Ferrothorn, Scizor that may try to set up/U-turn on me, etc.
Forretress @ Leftovers
Impish Nature
Ability: Overcoat
252 HP / 252 Def / 4 SDef
~Gyro Ball
~Toxic Spikes
~Spikes
~Rapid Spin
Forretress gaining Overcoat was a very nice addition to Hail teams, as Rapid Spin and entry hazard support is an absolute must for them IMO. I chose to go all out on physical defense as opposed to special defense, as it seems almost all special attackers carry HP fire nowadays. With max defense, I can switch in on things like Scarfed Terrakion, Mamoswine, Garchomp, etc, set up a layer of spikes of my choice, and then get the hell out of dodge. Although I abandoned my old Wish passer (Vaporeon) for better resistances on this team, Forry can still last long enough to set up 2-4 layers of Spikes/Toxic Spikes and Rapid Spin entry hazards away before biting the dust, which is really all I ask for.
Rotom-F @ Choice Scarf
Timid Nature
Ability: Levitate
4 HP / 252 SAtk / 252 Spd
~Blizzard
~Thunderbolt
~Volt Switch
~Trick
Rotom-F is amazing. With its new unique typing of Ice/Electric, not only does it cancel out its Ice type weakness to Scizor's Bullet Punch, but it now gains STAB on Blizzard and immunity to Hail, making it a powerful revenge killer for this team. If I see no Ground types or if I see a Chandelure on the opponent's team, this is what I'll usually lead with, just to hit something with a Volt Switch to get some damage and scout on what the opponent wants to do early on. Having both this and Abomasnow scarfed is a huge benefit to this team, as once the opponent's Pokemon are weakened from Toxic, Burn, and Hail, Abomasnow and Rotom can come in and usually sweep a weakened team with just Blizzard. Having two scarfers is also important because this team as a whole isn't the fastest, and this Rotom checks a lot of dangerous threats such as Dragon Dance Dragonite, Sword Dance Salamence, Dragon Dance Gyarados, etc.
Heatran @ Leftovers
Calm Nature
Ability: Flash Fire
252 HP / 4 Def / 252 SDef
~Lava Plume
~Toxic
~Stealth Rock
~Roar
A fire resistance for this team at its best. Bulky Heatran is pretty much my only check to things that would otherwise cause huge problems to this team, like Scarfed Genesect, Scarfed Chandelure, Jirachi, and all forms of Latios/Latias. Lava Plume is obligatory. Toxic, Roar and Stealth Rock are all there to stall, phaze, and rack up entry hazard damage. As long as this Heatran gets up rocks, wears down strong special attackers or burns/toxics something, then he's done his job.
Latias @ Leftovers
Bold Nature
Ability: Levitate
252 HP / 232 Def / 4 SAtk / 20 SDef
~Recover
~Toxic
~Surf
~Psychic
Latias and Heatran form an amazing defensive combo, covering each other's weaknesses perfectly. Vaporeon was originally here, but after succumbing to strong fighting and ground type attacks, I figured Latias would be a better choice, even with the lack of Wish passing. Recover and Toxic are pretty self explanatory and are there for stalling, and without Psychic, Conkeldurr would destroy everything on this team. Surf is there to hit the threatening fire and rock types hard, as well as giving me an attack that hits neutral on steel and dark types. The EV's listed even out Latias' defenses at 301 each, letting me take physical fire and fighting attacks more easily, as well as things like Thunders and Focus Blasts on the special side. The physical defense investment prevents me from being OHKO'd by Pursuiters as well.
Jellicent @ Leftovers
Bold Nature
Ability: Water Absorb
248 HP / 216 Def / 44 Spd
~Recover
~Will-O-Wisp
~Taunt
~Scald/Night Shade
One of the few ghost types with reliable recovery, Jellicent is probably the best spin blocker in the game, and offers me another great fire, steel and fighting resistance for this team. The set is pretty self-explanatory, but Night Shade might be a better option over Scald to slowly take out Reuniclus, who is a big threat to this team that lacks strong physical attacks and depends on status ailments, weather, and entry hazard damage to take out foes.
Prominent (but beatable) Threats:
Reuniclus, Conkeldurr, Tyranitar, Volcarona
Reuniclus gives me the most trouble, as outside of Taunting and stalling it out with Jellicent, slowly wearing it down the entire match, or Tricking it a Scarf with Rotom-F, I can't do much to it. Blizzard still does a nice chunk even after it has a Calm Mind boost though.
Conkeldurr is another big threat, as it normally runs Guts and can hit everything on my team sans Forry for SE damage. Usually though, I can play around it with Latios' Psychic and entry hazard damage.
Well, there it is guys. It has a few flaws, but it's still a nice team in a sea full of rain, sand and sun.

Abomasnow @ Choice Scarf
Hasty Nature
Ability: Snow Warning
16 Atk / 252 SAtk / 240 Spd
~Earthquake
~Giga Drain
~Blizzard
~Hidden Power Fire
Choice Scarfer #1. Although I usually don't lead with Abomasnow unless its against something like Politoed or Swampert leads, he usually comes in once something on the team dies just to get Hail going and to revenge kill. EQ is there for fire types like Heatran, Ninetales, Infernape, and Chandelure without a scarf. STAB Blizzard wrecks prominent threats to my team such as Gliscor, Landorus, Zapdos, Thundurus, Garchomp, etc. I chose Giga Drain over Wood Hammer for the sole purpose of surviving longer. Not to mention, I can invest more in Special attack to power up my main STAB move, Blizzard. HP Fire is there to hit Ferrothorn, Scizor that may try to set up/U-turn on me, etc.

Forretress @ Leftovers
Impish Nature
Ability: Overcoat
252 HP / 252 Def / 4 SDef
~Gyro Ball
~Toxic Spikes
~Spikes
~Rapid Spin
Forretress gaining Overcoat was a very nice addition to Hail teams, as Rapid Spin and entry hazard support is an absolute must for them IMO. I chose to go all out on physical defense as opposed to special defense, as it seems almost all special attackers carry HP fire nowadays. With max defense, I can switch in on things like Scarfed Terrakion, Mamoswine, Garchomp, etc, set up a layer of spikes of my choice, and then get the hell out of dodge. Although I abandoned my old Wish passer (Vaporeon) for better resistances on this team, Forry can still last long enough to set up 2-4 layers of Spikes/Toxic Spikes and Rapid Spin entry hazards away before biting the dust, which is really all I ask for.

Rotom-F @ Choice Scarf
Timid Nature
Ability: Levitate
4 HP / 252 SAtk / 252 Spd
~Blizzard
~Thunderbolt
~Volt Switch
~Trick
Rotom-F is amazing. With its new unique typing of Ice/Electric, not only does it cancel out its Ice type weakness to Scizor's Bullet Punch, but it now gains STAB on Blizzard and immunity to Hail, making it a powerful revenge killer for this team. If I see no Ground types or if I see a Chandelure on the opponent's team, this is what I'll usually lead with, just to hit something with a Volt Switch to get some damage and scout on what the opponent wants to do early on. Having both this and Abomasnow scarfed is a huge benefit to this team, as once the opponent's Pokemon are weakened from Toxic, Burn, and Hail, Abomasnow and Rotom can come in and usually sweep a weakened team with just Blizzard. Having two scarfers is also important because this team as a whole isn't the fastest, and this Rotom checks a lot of dangerous threats such as Dragon Dance Dragonite, Sword Dance Salamence, Dragon Dance Gyarados, etc.

Heatran @ Leftovers
Calm Nature
Ability: Flash Fire
252 HP / 4 Def / 252 SDef
~Lava Plume
~Toxic
~Stealth Rock
~Roar
A fire resistance for this team at its best. Bulky Heatran is pretty much my only check to things that would otherwise cause huge problems to this team, like Scarfed Genesect, Scarfed Chandelure, Jirachi, and all forms of Latios/Latias. Lava Plume is obligatory. Toxic, Roar and Stealth Rock are all there to stall, phaze, and rack up entry hazard damage. As long as this Heatran gets up rocks, wears down strong special attackers or burns/toxics something, then he's done his job.

Latias @ Leftovers
Bold Nature
Ability: Levitate
252 HP / 232 Def / 4 SAtk / 20 SDef
~Recover
~Toxic
~Surf
~Psychic
Latias and Heatran form an amazing defensive combo, covering each other's weaknesses perfectly. Vaporeon was originally here, but after succumbing to strong fighting and ground type attacks, I figured Latias would be a better choice, even with the lack of Wish passing. Recover and Toxic are pretty self explanatory and are there for stalling, and without Psychic, Conkeldurr would destroy everything on this team. Surf is there to hit the threatening fire and rock types hard, as well as giving me an attack that hits neutral on steel and dark types. The EV's listed even out Latias' defenses at 301 each, letting me take physical fire and fighting attacks more easily, as well as things like Thunders and Focus Blasts on the special side. The physical defense investment prevents me from being OHKO'd by Pursuiters as well.

Jellicent @ Leftovers
Bold Nature
Ability: Water Absorb
248 HP / 216 Def / 44 Spd
~Recover
~Will-O-Wisp
~Taunt
~Scald/Night Shade
One of the few ghost types with reliable recovery, Jellicent is probably the best spin blocker in the game, and offers me another great fire, steel and fighting resistance for this team. The set is pretty self-explanatory, but Night Shade might be a better option over Scald to slowly take out Reuniclus, who is a big threat to this team that lacks strong physical attacks and depends on status ailments, weather, and entry hazard damage to take out foes.
Prominent (but beatable) Threats:
Reuniclus, Conkeldurr, Tyranitar, Volcarona
Reuniclus gives me the most trouble, as outside of Taunting and stalling it out with Jellicent, slowly wearing it down the entire match, or Tricking it a Scarf with Rotom-F, I can't do much to it. Blizzard still does a nice chunk even after it has a Calm Mind boost though.
Conkeldurr is another big threat, as it normally runs Guts and can hit everything on my team sans Forry for SE damage. Usually though, I can play around it with Latios' Psychic and entry hazard damage.
Well, there it is guys. It has a few flaws, but it's still a nice team in a sea full of rain, sand and sun.