Summary

Remixed the original case to fit a Raspberry Pi 3B. I've used this model for the fitting https://www.thingiverse.com/thing:3325492.
The only parts that were changed are the main frame of the case and the lateral lid with the holes for the power and HDMI cables, the other parts are the same.
The holes for the USB ports turned out a little smaller than the ports on the real Raspberry Pi but it worked fine.