http://www.amazon.com/gp/product/B006TVQTFE
http://www.amazon.com/OCZ-700W-StealthXStream-Power-Supply/dp/B001IZ5O0M/
I own these two already, the first one is brand new still unopened, the second one was running a 6990 for a while in the spring without issue.
If neither of those can power two at the same time with overclock I'll probably go for one of these three: (unfortunately I don't get paid till friday sadface)
http://www.amazon.com/gp/product/B006TVQTFE/ (The 900 watt version)
http://www.amazon.com/Corsair-Gaming-Series-800-Watt-GS800/dp/B00ALSNDM8/
http://www.amazon.com/gp/product/B0029F21LA/
Okay, thanks for the advice, that's what I was thinking as well. It's just a bummer to know that if my 3 cubes ship during the week I'll only be able to power 2 until I get paid and can afford/order one of the nicer power supplies.