Yes, it looks like I can find them, at least in the U.S.
Breakout board (fits 2 PSUs):
$13 eachPCIe power cables:
$19 for 10IBM 94Y8118 900W 80+ Platinum supply:
$20 each. Make sure you specifically buy the '94Y8118' version manufactured by Emerson, because it has the highest efficiency.
It looks like you can get 1800w of power for $72 in total at Platinum, which isn't a bad deal at just $40/kW. But I would only run 1500w through the breakout board, just to be on the safe side.
If you went with the 80+ Gold HP DPS-750RB, that would cost $47 for 750w of power. That's $63/kW.
So IBM is clearly a better deal, especially after you consider the $8-9/kW of savings every year from the increased efficiency.