I designed this to be a bit bigger, take a standard 12mm switch, house an RP 5, and a convenient power button. I also added a standard 40mm exhaust fan hole.
I designed this to fit a hat as well but I haven't tested it.
I'll happily share the STLs if anyone is interested. I am working on posting to Thingiverse now.
It looks like this should fit any model Pi but naturally YMMV.
I wanted to leave it open so it's more universal in what can be fitted in there but I may make a revision in the future that is more model specific if I end up printing another one for a 5.