This is my take on a mini stx Louqe Ghost S1. It houses a mini itx motherboard and a pico psu.
I have found if you take the shroud off an ssd it will tuck in the back.
The cooler clearance is around 58mm, something like the Is-60 from Id Cooling or the Akasa NeroLX2 will work well (these are the only ones I've tested, many more will work).
I have provided a hole at the back for the psu connector, this may have to be drilled out. I have left the front blank with no button hole so that can be customised however you want, I drilled a hole and used an anti-vandal switch.
Overall measurements are around 200x185x60mm so can easily be printed on something like an Ender 3. The only supports needed will be for the I/O shield.
Screws used throughout are 3.5mm (No.6) by 13mm countersunk.
These can be stackable as there are holes in the bottom of each, I will hopefully be designing more soon, please let me know if you have any ideas for other modules.
Any questions please ask.
Make sure to put plenty of supports in the I/O shield otherwise it will sag.