This is interesting. Its the first benchmarking results for the quad SLI 7900. Even though it performs well in cetain games it seems to be a very unstable and suffers from slow memory. Check it out and see what you think. I know I'll be waiting (like I've got the money for one. LOL)
http://www.xbitlabs.com/articles/video/display/geforce7900-quad-sli.html
http://www.xbitlabs.com/articles/video/display/geforce7900-quad-sli.html