Again, I've considered Mr.Mime lead because of sound proof, encore, and his general movepool but I just assumed that because of his physical frailty (U-Turn) that he wouldn't be a successful lead.
And if Mr. Mime is deemed a usefull lead I'd have to question Exploud as a plausable lead.. Sound Proof, High Base Hp (104), awesome movepool that includes taunt, overheat, and other things, and he has decent offensive stats. Only thing he lacks is speed but I don't know if that is entirely an issue since he is capable of taking a hit.
Timid Mr. Mime speed ties with Timid Roserade and almost always prevents Spike variants from setting up or sleeping with Taunt. Barrier or Reflect (the former for Baton Pass and the latter being part of the dual screens strategy) can be used to defend against Physical leads. Taunt shuts down nearly all sleepers (except Scarf Roserade or a lucky Persian) so Lum Berry isn't needed. He makes very good use of Leftovers or Light Clay. My variant was a Dual Screen version that actually pulls off the set better than Uxie with higher speed, Soundproof nullifying Bug Buzz, and Taunt.
Mr. Mime@Light Clay
252 HP/252 Spe/4 SpA (or D, doesn't matter)
Timid/Soundproof
-Taunt
-Psychic
-Reflect
-Light Screen
It loses to Ambipom, Arcanine, and Persian, so have a switch in to those (Donphan works well).
With Light Screen, Yanmega can't even 3HKO him with Air Slash, he'll also wall the hell out of Roserade and Moltres, even the LO variants. Taunt prevents setup and turns Registeel (who for some reason is a common switch in to Mr. Mime) into setup bait for bulkier stat-uppers like Leafeon (whom I use on that team), any Subpuncher, and Bulk-uppers (although they are very, very rare).
Exploud, with 68 base speed, is ridiculously slow, and with 63 base SpD he's not lasting long against Yanmega anyway. He is, however, a very good Baton Pass recipient. He can make use of passed NPs or SDs (Return and Hyper Voice are both very powerful STABS on both sides) and can't be Roared away. As a lead, though, he's not beating much of anything.
I paired that Mr. Mime with Leafeon:
Leafeon@Leftovers (although Lum Berry is also a good option, I just tried both and liked lefties)
132 HP/126 Def/252 Spe
Timid/Leaf Guard
-Swords Dance
-Wish
-Leaf Blade
-Baton Pass
Always gets the pass off from behind screens and is absolutely deadly when paired with Flash Fire Arcanine to receive the boost and take the fire attacks aimed at Leafeon.
Random Thought: Why does Soundproof not prevent Taunt?