AMD's soon to be officially launched AMD 790FX board will be able to work with four RV670XT or PRO cards. We are not sure when will the final driver will be available, but the good thing is that four RV670XT cards should cost only US$200 more than a single Ultra.
This crazy Quad RV670XT setup will be something that ATI can sell for some US$800, and that includes the price for all four cards. For ATI's sake we hope that four RV670XT can beat two 8800 GT in SLI or two 8800 GTX / Ultra cards; but still Nvidia might be winning with its tri SLI powered three 8800 GTX / Ultra cards.
If you look at the price, three 8800Ultras will sell for more than €1600, while the quad crossfire should sell for at least half of that price. At least this sounds interesting to play with.