Like I attempted (but apparently failed) to explain, that's pretty much what they do now - any time real money is exchanged for virtual goods/money it's treated like a sale and taxed accordingly (after all, we've been exchanging money for bytes for quite some time now). I can see them deciding to treat it as something other than a sale for tax purposes, which would suck because it would increase the complexity of an already-overly-complex tax system.