I'm also trying to do this - sent you a friend request on these forums.Looks like quite the feat and I think there would be a LOT of interest in seeing how you did this as poweredge motherboards and xeon x56xx cpus are really cheap on the secondhand market and perfect for home server projects or even cheap-o workstation/gaming rigs!
I recently purchased an R410 motherboard with the intention of using an ATX power supply on it. However, upon reading the Technical Guide (page 25), I realized that the 24-pin connector is non-standard on the R410. Would a ATX 24-pin to Dell 24 + 16-pin adapter work on this motherboard? I cannot for the life of me find a wiring diagram for that adapter but I also don't want to fry the motherboard. Does anyone have any ideas or experience with this board/adapter?
Poweredge R410 V2 with standard ATX Power Supply