Welcome to the board!
I'm afraid that you can't avoid getting into hardware modding. I don't think that you need any deeper skills in electronics or programming, though.
There are a few DIY projects that does locking caps lock keyboards with modern Mac and PCs.
There are some issues, though, especially with programs that try to set/unset the Caps lock mode/light on their own accord.
* With
Hasu's ADB-to-USB adapter firmware, you could use a vintage Apple keyboard with a modern computer. It will translate the locking Caps Lock key's codes into presses from a non-locking key.
You will need a
Teensy microcontroller board and solder the connectors to it and then download Hasu's firmware onto it.
I think that this might be the easiest option.
* There are also people who have built their own keyboards with locking Caps Lock switches, and with custom microcontroller firmware that do have similar emulation.
Look in the threads about the Phantom firmware. Several guys who built the "Phantom" DIY keyboard kit are using MX Lock switches for Caps Lock, Scroll Lock, etc.
* User "Aleksander" on Deskthority's forum
Modified an existing keyboard to use MX Lock.
He used the Poker, which has PCB-mounted switches and no metal plate. He wrote a custom program for a tiny microcontroller just for the switch.
(Has he posted here too?)