Now that the new 2009 Mac Pro has the processors and ram on a completely removable tray would it be possible to just swap or upgrade the tray. Example, I have a 2009 2.66 Quad Mac Pro, could I just slide out my tray with the 2.66 Quad and slide in a different tray, like an 8 core one with the two 2.26 quads? I know you cant just buy the trays at the moment but in a few years could I maybe pick up a faster processor tray on ebay and put it in my machine? Does anybody know why this wouldn't work? (other hardware differences between the 4 and 8 core Mac Pros other than whats on the processor trays for example)