Lol first, that's awesome, and second everything in WoW in bankable, :P, but I doubt that you'd get banned. I mean what could they say in a ticket? "This guy has a name that I want but he already has it reserved and he says the only way I can get it is if I buy gold from him" Sounds ridiculous to me. If they treat names like any other marketable item in the game then you should be fine.