10-boxing is fun, but Naxx, OS, and 2 of the VoA bosses are just about all anyone has done so far. Most ToC and even Ulduar fights require a few too many toons doing specific things and it becomes hard for one person to handle it all.

Still, I enjoy it. I usually run dailies or a heroic on one team in the down time I have single-player raiding ToC10.

You might want to consider a hunter and a boomkin - the hunter to suck up all the attack power gear and the boomkin to provide the hit bonus. That's a lot less hit you need on a lot of other toons if you have one boomkin along.