Stay far away from Tt PSUs. I have seen and experienced alot of trouble with them in the past.
All of these units are $250 and under:
XFX ProSeries 1250w (Seasonic rebrand) Out of Stock @ newegg (maybe fine elsewhere or set auto-notify)
LEPA G1200-MA (Enermax rebrand) Out of Stock @ newegg (maybe fine elsewhere or set auto-notify)
SilverStone Strider Gold SST-ST1200-G In stock
Rosewill LIGHTNING-1300 1300W Out of Stock @ newegg (set auto-notify)
All good PSUs and up to the task. 4 7950s will come very close to 900-1kw and thus a 1000w unit is really on the red line. Most 1200w units are only a couple bucks cheaper as it is.
The LEPA is best bang/buck followed by the Silverstone. I am currently using 2 of the LEPAs and for 9 months now they have been going strong @ roughly 1kw load each.
I have a Silverstone 1500w unit on 4 290s and it's been rock solid for the last week. I would expect the 1200w unit to be of the same build quality.
The Rosewill units are Newegg's house-brand so you won't find them anywhere else, but regardless they are worth mentioning as they have good user feedback / 3rd party reviews that reflect a solid build quality.