That's strange. Google found plenty of hits.
The case looks like it will take any standard ATX PSU. And the 7900GTX only needs about 7 amps. For that system, I'd get a Corsair 400CX (30 amp 12 volt rail)http://www.newegg.com/Product/Product.aspx?Item=N82E16817139008
That's all you really need. Besides, the Ultra is about one step above junk.
The Ultra PSU is junk.