Um... how about...
Articuno @ Leftovers/Brightpowder
Bold
Pressure
252 HP/129 Sp Def/129 Def
Mind Reader
Sheer Cold
Double Team
Roost
Double Team/Roost until you get 6 DTs in, then Mind Reader + Sheer Cold their whole team. Substitute might be an option here as well (that stops OHKO moves, right?).