I have kinda been multiboxing... But not in the style in which you are presenting.
I got a friend to RaF link me, we get to level 8 on 2 Palas, I multibox my DK and the Pala, and boost us through RFC 'till 16 I think, then move on to the next dungeon, etc etc.
We're lvl 48 now after 2 days, with...