I tried this, but eventually ended up with Paladin/Mage combo. Two mages are good for arcane explosion, but targeting with Bliz/Flamestrike/Cone of Cold is a pain on two at once and not as efficient as two individual players. I'd rather have a tank/healer who can hold AoE aggro like an AoE/prot spec pally, then sit back with the mage and rain blizzard/flamestrike. It may be slightly lower dps, but it's a lot less risky and you don't have to share loot between two clothies. The paladin/mage was my favorite of the groups I dual boxed with.