I use this on my MakerFarm Prusa i3v 10". There's probably better ones out there, but I wanted to make my own (I didn't even search).

I didn't try other PSUs in it, but I left the outside of the mount open in case I decided to use one with a large fan -- haven't tested that though. I've included AutoDesk 123D files in case modifications are needed.

Getting closer to prettying up all the wiring now that I have this :D

Print the base 2x
Print the inside 1x
Print the outside 1x

Use acetone to chemically weld all the pieces together. The mount is designed so that you can slide the PSU out the back of it, however I'd highly recommend placing the pieces around your PSU when you chemically weld it. Then clamp it all together and give it time to dry.

Use a pen to mark your holes where you want to mount it, then drill -- I only drilled 2 holes for mine. I used some M3 bolts to secure it to the frame of my Prusa.