Have you considered rolling a dk team? You are keeping your existing accounts with high level characters on them, you could have a complete team to 58 and hit outlands in an hour or so. Level them up and boost whatever classes you want with them. The other cool thing is you get to have a high level PVP team to look out for your lowbies when questing.

Edit: I somehow missed the above posts when making mine, I guess I second the dk team idea ;)