I was sadly unable to improve upon my 83 win streak using my Darmantian team. Usually I'd get haxed out, though I did find some troublesome pokemon that were impossible to beat with my team. Since this is higher than 70, I thought I might as well post it. Unfortunately I don't have any picture or battle video proof because I didn't take a picture at the time my vs recorder displayed the record.
So here's the team:
Darmanitan @ choice scarf
This is my star. Pretty simple to understand really. Flare Blitz whatever dies and U-turn out of whatever won't. The other moves are filler, though I did use them occasionally for particular rock types.
The EVs are simple. Max attack obviously. 236 speed ensures I hit 217 speed, hence outspeeding the fastest forms of Accelgor (this is the fastest thing that scarf Darmanitan can hope to outrun and any more speed investment is a waste). The leftover EVs are placed in its defences, though this makes no difference really.
This thing is borderline noobish. The thing that stops it being completely noobish is that some thought and care is required in regards to what you should stay in on and what you should U-turn out of. The general starting rule that I went by is "if it is weak to fire it dies; if it resists fire it lives." From my own testing this is pretty much always true (there may be some exceptions). From there, it's about using your best judgement. Sometimes it's fairly easy. Obviously a frail opponent like Mr. Mime is going to die. However, sometimes pokemon you'd think would die can actually survive, often because of the unusual EV spreads some of these pokemon carry. For example, Volcarona 3 and Mismagius 4 barely survive Flare Blitz (not that either of these are particularly threatening, but it demonstrates that you have to be on the look-out).
You also need to watch out for things like focus sash, sturdy, heatproof and thick fat. I lost one streak because I tried to kill Glaceon without releasing it had a focus sash. It survived and set up hail. The next turn, I miss due to snow cloak and am promptly killed by Hyper Beam. I can't remember the rest of the battle, other than the fact that I could have won if Darmanitan hadn't fainted. From then on, I always played conservatively in these situations and U-turned out (this approach has worked out so far).
Rotom-W @ leftovers
Hidden Power [Grass]
I chose this thing because it can single-handedly take down the 2 trainer types that Darmanitan struggles against: Fishermen and Parasol Ladies. The only water type that it can't beat is Ludicolo, though these aren't that threatening to my third team member anyway. It can also do well against Hikers and Workers (though this depends on what they use).
This is a different Rotom than the one from my other singles streak. With HP grass, it can now kill those pesky water/grounds (especially Quagsire and Gastrodon because they can be immune to Hydro Pump due to their abilities). Volt Switch has been great because it can be used to finish off an opponent and get Darmanitan in for free. This is especially important because of the choice scarf, as it allows me to pick the move for the next thing that comes in rather than be forced to use what I was locked into before.
The thing that stops Rotom from being perfect is Hydro Pump. Its accuracy is starting to annoy me now (probably because I'm using it a lot more in this team than in other teams). It is what cost me my best streak with this team. I wish this thing could learn Surf or Scald...
Latios @ life orb
This was designed to check dragons. Too bad it can't switch in to dragon moves! Still, it served as an excellent backup sweeper when Darmanitan dies. Its ground, grass and water resists give plenty opportunities to switch in and do damage, which is handy.
Dragons - these were the biggest problems to deal with. Latios can kill them easily with Dragon Pulse, but it can't risk switching in to a dragon attack (especially physical ones, though Draco Meteor hurts too). What's worse is that Rotom isn't bulky enough to take them either (plus it's walled by them). Often I have to sacrifice Rotom to get Latios in safely which is just not ideal. The worst dragon is Dragon Dance Haxorus. If this thing gets a single Dragon Dance up, I'm done for. This has ended 2 attemped streaks. Of course, if Latios is out when a dragon comes in, it isn't a problem.
Strong rock attacks - I lack a rock resist. Strong rock attacks like Choice Band Archeops' Head Smash and Rhyperior's Rock Wrecker hurt. I at least have Superpower and Rock Slide to deal with them, but locking myself into these moves is unideal. Also, there's no avoiding Rock Wrecker so I have to sacrifice something to it (though at least I can revenge kill and hope the following pokemon aren't threatening).
Hax - it seems pointless to bring this up, but since this is a hyper offence team that doesn't employ any methods to protect itself from random crits, freezes and other stupid crap, this can be a problem.
Since this streak was not exactly recent, I only vaguely remember how I lost. I think it went something like this:
I send out Darmanitan and the opponent sends out Bastiodon. Since this has Sturdy, I decide to U-turn out to Rotom. I deal a small hit and Bastiodon uses Curse. I attempt to kill it with Hydro Pump, but I miss. Bastiodon Rock Slides for about 40% damage. I miss 3 more Hydro Pumps and Bastiodon Curses 2 times and kills me with Rock Slide. At this point I have to decide whether to sacrifice Darmanitan or Latios. Because Latios can handle more threats, I send in Darmanitan. I use Superpower, which deals about 30% damage. Bastiodon recovers with Sitrus Berry and kills me with Rock Slide. I send in Latios. I use Thunderbolt to bring it to about 10% health. Bastiodon misses the Rock Slide (Phew). I kill with Thunderbolt. Now I'm praying for an easy ride from here. Instead, the opponent sends in a Focus Sash Accelgor and I know that it's over. It kills me with Bug Buzz.
I may have remembered some of that wrong, but the main parts (where Bastiodon avoids 4 Hydro Pumps to set up and destroy me, and where the opponent just happened to have one of the worst possible things for my last pokemon to face off against) are correct.
This was a fun team to use because it was fast, though I think I'm gonna try something else now.