I modified this case bottom because I loved the look of the mountable rpi printable case, and the printrboard bracket idea, but ran into an issue with the fact that the holes wouldnt line up at all. I modified it in meshlab and freecad so that the holes will be identical to those of the printrboard, so the rpi can be placed on that bracket.
Just print out this base and print out the top from the mountable rpi server case in the sources, then use zip ties, or screws to attach it to the printrboard bracket.
Edit: mirrored printrboard mount is uploaded so you can use it on the other side of the prusa and it would look right.
This is for a prusa I2, but can be modified to work on really any 3d printer, this will only fit the original raspberry pi B due to only it only having the 2 usb ports vs the newer RPI systems.