Fought a GBU Rated match against some Japanese kid with like 1850 rating. Here's his team:
Breloom @Focus Sash
-Spore
-[Focus Punch?]
-[Protect?]
-[???]
Liepard (DW) @Leftovers
-Substitute
-Assist
-Swagger
-Foul Play
Ditto @???
-Transform
So, here's his strategy. Spore with Breloom, then switch to Liepard. Prankster lets him set up a Sub no matter what. Swagger, then use Foul Play - it's especially devastating against physical sweepers. If the other poke wakes up, he uses Assist. Assist can't select from any teammates' moves except Spore (I'm guessing about Focus Punch and Protect, since they can't be selected by Assist) so basically Assist = Spore.
Anyways, this team is evil, and it's probably impossible to beat unless you're either using a Chesto Shuckle or have seen it before. Going from the guy's rating, it works frightfully well...