The newer winterfell nodes [1] have made their way to ebay at sub 100$ and do not have the exotic power requirements of the earlier dual sled windmill nodes. You can easily power them off of a converted server power supply via diy [2] or commercial [3] means. Windmill nodes have more space on the pcie riser and quieter fans going for them as well.
1) https://www.ebay.com/itm/Quanta-Winterfell-Barebone-Node-2x-... 2) http://colintd.blogspot.com/2016/10/hacking-hp-common-slot-p... 3) https://www.parallelminer.com/product/breakout-board-adapter...
The single PSU of the chassis that supplies power to both nodes does require 220V power, but I solved this easily enough with a 2000 watt step up transformer off of amazon. I've also jerry rigged up an additional ATX power supply as the native chassis psu doesn't have 6 pin power connectors to power the GPUs.
I've never calculated how much power the thing pulls under full load, but considering that I've never had any instability I've got to assume it's less than the 2000 watts tha transformer can handle + the 400 watt ATX psu for the GPUs. I've got flat rate electric from my landlord, so it's essentially free to run for me.
[1] https://www.ebay.com/itm/QUANTA-OPEN-COMPUTE-SERVER-2x-NODES...