If for some reason you really want to use a high end card and have the chance to put it up for resale later i would into the nano that was just announced. Should be around 400$
A high end psu could easily handle a few of these and if you want to mine via a case you could get three in a standard atx with 800w psu able to power 3.
Cool. I had no idea they had released those. They would be real nice in a case. As it is now I run 2 7970's in 3 cases and 2 pair r9 290's in 4 other cases. Too bad I don't mine that much anymore. Mostly new coins right at beginning if I catch it.