I got my PS2TOSERIAL a few days ago and it works flawlessly! Thanks for releasing this and thanks to SerdaShop for carrying it.
Sebastian's case also works great. I didn't have the right size screws, so I just wrapped the whole thing in tape and cut a square in the tape on top for the vent holes.
I saw SmooBandit's idea (in this post) of using the PSU's own 5V supply to power the board and I wanted to see if it was possible to go the rest of the way and make it completely internal (with just a PS/2 port exposed through a plate on the back of the case). My 486 had an unused internal COM header, so it seemed like this should be possible. I still wanted the option of using it externally, so I ruled out any soldering (which would make the conversion mostly trivial). The final adapter chain looked something like this:
B: PS/2 panel mount extension cable
C: Any short A-to-mini-B USB cable
D: CRJ 4-Pin Molex to 5V Female USB
E: DB9-Male to IDC 10-pin serial adapter (DTK or AT/Everex)
Just plug everything together and now your retro computer has a PS/2 mouse port on the back. 😁
For E, my 486 happened to need the DTK version of the 10-pin cable. To find out which pinout you need, just unscrew the two nuts and peek at your existing serial jack, comparing it to the pictures at the bottom of each of those PCCables pages.
It would be cool to see an internal PS2TOSERIAL variant in the future. I'd buy one of those, too! It would just take replacing the USB power with a 4-pin floppy power header (and rotating it 90 degrees) and changing the PS/2 part to one with mounting screws for a plate. It'd still probably be best to leave the serial port there internally. Then the user could provide whichever version (DTK or AT) serial header they needed.