There is really no way that is actually legitimate. If you actually recieved a quad core for beta testing like some poeple over at XS, would you really put that thing up for sale??
I see where you are coming from. I suppose you could...but I wouldn't give up a chance to play with that kind of technology for that kind of money, which you can probably convince some moron to pay later. Of course, if you are done with testing its capabilties, then by all means, I would sell it.