PC Review have a new review of the Supermicro X7DWA-N, a high end motherboard that allows you to use 2 x Quad Core CPUs and up to 64GB of RAM A quote from the article:

I had the opportunity to spend some time testing and evaluating this motherboard with two sets of CPUs and two types of memory. First using two X5482 Harpertowns (3200/12mb/1600) and 4x2 gig of Transcend DDR2-800 FB-Dimms, and later on using two E5450 Harpertowns(3000/12mb/1333).

This EATX board is built using the newest 5400 Seaburg chipset with 1600FSB support built in. The layout is a typical EATX 12x13” design and like previous versions uses 24, 8 and 4 pin connections to the motherboard. With this new series, a 4 pin Molex connector is added to the board for users with higher power needs. There are 8 Dimm slots for quad channel memory support (up to and including DDR2-800 FB-Dimms) for a maximum of 64 gigs. The board comes boxed with 6 SATA cables, I/O shield, IDE cable, and an excellent manual and Cd with all needed software and drivers.

>> Supermicro X7DWA-N Motherboard Review