Update: Febuary 10th 2022, added a setting to print the original case and stl without the Raspberry Pi cut-out.
Because of power issues when using power from the MK3 board, I have changed to an external case hooked to the frame just below the case the advantages are :
It needs :
Print with 4 or 6 walls for better screw support.
Inspired by this from @Ystrouzas I took the time to modify the original OpenSCAD files from Prusa, you have variable "RaspberryType" at the top of the .scad file that specify which version fo the Pi you want.
I also included .gcode files for a Prusa MK3S and .3mf project for your slicer.
Printed in PETG
I also have a Github of the mods I did fork from Prusa:
Frank's 3D Shop Github Link.
This is a remix from https://www.prusaprinters.org/fr/prints/9284-prusa-i3-octoprint-raspberry-pi-case
P.S: I did not test this version with reinforcements at the bottom, and I did not test the Pi 4 version I went from sizes found on Raspberry Pi website.
The author remixed this model.