This is my attempt to make a compact size case for a Raspberry Pi 4 Server that can be attached to the wall. I also added a hole for the Raspi 4 Fanshim but due to the design you cannot just leave the Fanshim on the Raspi Board but need to use a connector ribbon if you want to use it. Don't forget to use plastic nuts to avoid vibrations!
I designed the holes to hold the raspi board for metal inserts for M2.5 screws.
There is still on problem with one of the feet! If you screw the HDD from behind it collides with one of the feet. You could either drill a small hole in the according foot or only attach the hdd with 3 instead of 4 screws. What I did to attach the hdd is cut the cylinders over the 4 holes and replace them with small rubber plates. That should help with eventual vibrations.
One additional note about the design: some ppl. might want to use a RAID setup for their Raspi Server, but the problem is that you cannot operate 2 HDDs with the power supply of the Raspi. Since RAID is not intended as a backup but mainly to keep the device being operational all the time, I decided against a RAID setup and therefore for this design. Don't forget to backup your data none the less!
Please also note, that I slightly improved the design since printing out my prototype. The pictures of my model are therefore slightly different than the files. Furthermore I didn't print the cover because I intend to make it out of wood with my future CNC.
You might as well check if the opening for the HDD cable is big enough for you, as there seem to be different models available.