I have originally wondered about the server PSU possibility. I got a good deal on my rosewill lighning 1300 watt($139) and my Corsair's($49 for the 750 watt 80plus bronze) ($29 for 600 watt 80plus Bronze). The reason I didnt do the Server PSUs was I couldnt find the breakout board option for sale at the time and I couldnt find info on efficiency.
How is the efficiency of the Server PSUs as compared to the 80+ Bronze, Gold or Platinum ATX PSUs?
Also, is it any easier on electric and/or heat to run on 220/230 volts AC as opposed to 110/115?
Server PSU's are generally at least 80% efficient, and this 2000w one is 90+% at 50+% load.
not sure i fully understand your question about "easier on electric and/or heat" but things run more efficiently (ie lower overall watt usage) on higher voltage because they require lower amperage which means less of your electricity is converted to heat (due to resistance). if you want to better understand this link may help (or may just confuse your more) -
http://www.physicsforums.com/showthread.php?t=608751.
V (volts) x A (amps) = W (watts)