So I finally had enough parts of my Xserve to test it to an extent.

Time was short so I neglected to borrow RAM from my MDD or the graphics card from my B&W, but I connected up the PSU, logic board, ATA board, drive interconnect board and front panel board, held down the lock button and punched the power......

Success!

Fans and lights everywhere they should be. Its looking good for a firewire boot test in the near future.
Plus a drive module is winging its way.....