where do they sell power supplies like that? Is it dell? did it come with that board also? 
Yes it is a Dell server PSU 750w here is who makes and sales the boards. There was a group buy going on for them I just bought mine direct. You can get the board or the whole setup.
http://www.gekkoscience.com/products/D750_supply_breakout_board.html
some advice they are a shock/short hazard and not too good with power use.