Just started a new trio that I eventually will use for 3v3 arenas.

Shaman (Resto) - Phuuk
Warlock (Demo) - Phuuc
Warlock (Demo) - Phuuq

Current Level: 23

Edit: I am finding so far that 3 chars with 2 pets can function in a 5 man setting rather well. With my setup, I have 1 healer, 2 DPS, and 2 tanks. The VW's have just as much health and armor as a true tank. I know this changes at higher levels, but is working great for now.

Instances
RFC - cleared at 15, no wipes. VW's tank, shaman heals, warlocks dot + drain
WC - cleared at 22, no wipes. Took a long time though, almost 2 hours.