This power supply cover was designed to fit a 12V 30A PSU from Amazon, which is much wider than the original Prusa i3.
The other item to note is that my DIY Prusa frame was made from ~3/4 plywood, so this PSU cover was designed to accommodate the extra frame thickness. If you're inteterested, the DIY Prusa was built based on Thomas Sanladerer instructions.
I also decided to permanently install a power cable and using a 20mm rocker on/off switch.
Part Number: ??
Description: EAGWELL 12v 30a DC Universal Regulated Switching Power Supply 360w
PSU Dimensions: 114 x 50 x 215 mm (actual)
This does not appear to be available from Amazon anymore. :-( However there are other PSUs on Amazon seem to be exact clones.
I sliced with Slic3r (Prusa edition).
Was interesting that supports were built for the embossed "Prusa i3" lettering.