If you are going to do this, get a socket LGA1366 based board and CPU's. There is a significant difference between LGA1366 and LGA771 stuff. LGA1366
* is newer
* DDR3 memory
* price is the same
Also, get a motherboard pulled from a desktop workstation if possible, or at least from a tower server. Modifying motherboards from rack server is PITA. You have different power connectors, usually just 2 usb ports, weird form factor, not accessible PCI-E slots if not using riser etc.