Summary

Do you dislike long cables from standard PSU? Well, here is box to hide it from your eyes and make your printer a bit nicer.
And there is power switch too!

Instructions

The box is approximately 70x160x89 mm big. Just enough to print it on normal Prusa Mendel.

You cannot cut unneeded cables from the PSU because you will lose the warranty, if the PSU is just brand new. The easy solution is to make a cable box for it, so you wont see ugly large cables from the PSU.

You must print top, bottom and three clamps for it. See the images how it goes.
Only some words: the photos has first version box. The STL files here are already improved and should now have less problems when putting top and bottom together.

You drill 4 holes in top part with 8mm drill, but don't go too far (max 38mm deep) or you cannot close the box anymore. So you don't need very large screws.
If done, then drill it with 3mm. In bottom part, drill it with 2,5 mm.
Drill the clamps with 2,5 mm holes if you use screws (or 3mm hole if you use bolts), but in clamp parts in top and bottom parts, drill it with 3 mm.
Use 4 screws (20mm is large enough) to close top part on the bottom part.

You may mount bottom part first on the rod of the printer. Then let it rest on the small box below. Solder first for the power-on switch. Try put the cables inside the bottom part.
See the photos how it goes well. Some PSU has large cables, so my Coolermaster PSU cables will just fit inside.

Don't forget the small hole at the side. It's for 12V cable to the printer.

You can use it together with my PSU mount on http://www.thingiverse.com/thing:40672

It's designed with Google Sketchup.
Good luck!

PSU cable box mount