You are focusing on the wrong thing here.
Consumer brand PSUs, the stuff you might find at a Best Buy or something, have universal mounts. That means any of them should technically fit in a case that uses universal mounts. The Rosewill V2 is this sort of case.
If you had a DELL or HP or Acer computer, they may or may not use universal mounts, but Rosewill, Antec, Corsair, and other stuff marketed to consumers as case only rather than full system will always use the universal mounts.
However, you can't just get any PSU and expect it to work.
How much power the PSU can deliver is of extreme importance. If your PSU can't power the system that it will be connected to, you will have all kinds of problems up to and including the system not turning on at all.
I can't tell you what will and won't work with your system because I don't know what parts you have or intend to have.
I can tell you that an XFX Pro 650w Core, like I have, will handle pretty much any single video card setup you can throw at it. After rebate it usually comes to about $60 to $65.
Note that I said XFX 650w. Not just any 650w will do. Brand is more important than wattage. The different makers use different quality internals and that makes a major difference in the amount of power a PSU can put out.
If you have just 1 video card, you could go with the one that I said and you would 99% likely be fine (if the card doesn't cost $300+ anyway).
If you intend to use more than 2 cards, OR if your video card costs more than $300, OR if you feel your system is probably not going to use very much power
You can list all your specs that you intend to have and I can tell you if you should get some other one instead.
If you don't intend to have any video card, you would be fine with an XFX 450w instead.
Any single card not over $300 should be fine with an XFX 650.
Any 2x card setup should probably be fine with an XFX 850.