Cray seems to have already unveiled the XE6 model of their monster computers, and it's based on the 8 or 12-core AMD Opterons!!
Impressive is that they managed to create an architecture that can scale to over 1,000,000 cores!

http://www.cray.com/Assets/PDF/produ...E6Brochure.pdf

I can only imagine the cost of such a monster... maybe with the purchase of one of these you get a free small nuclear power plant to feed the power to the beast!