I'v put up a new post on my website about a 48G machine that I am very sure will do 10, if you wait for non-ecc 8G ram then you can use most any i7 or sandy bridge board. Although in a few months bulldozer info's as to ship date and availability from AMD should be available.

I suppose with 10 the best option would be a lessor video card for the main and another card for the 9 tiled slaves? Ya gonna be rough running the slaves at the same resolution as the main. How many monitors do you have and how are they attached to the video card?

A server board with 2 cpu won't share the ram between both so putting the wow folder in ram on a 2 cpu board won't happen unless you go to 96G ram.