I presume the real money idea won't really get off the ground. You see, not all gamers are into business, trading and that whole tactic behind it. This is the case with most SINGLE PLAYER fanatics like myself.
When I find an epic weapon that I can't or won't use, I'm not going to scour the entire AH to see for how much I can sell it. In this way, I'll put the imba weapon on the AH for 5000 gold, while another guy put it up for $25,- (its that awesome). Without doing the research, logic tells me there's tons and tons of players like myself, who will unknowingly collapse the economy.
The joke's on Blizzard for forcing the multiplayer feature upon the singleplayer kinda people.