I'm currently playing with Warrior(prot)/Druid(resto)/Mage(arcane)/Priest(shadow)/Warlock(destro) in Wotlk heroics.

The priest and warlock could easily be replaced with 2x mages.

It works really good, but you gota watch the channeled spells - they'll cause your toons to "rotate" when the boss moves and screw up your party strafing.