I bought an actual cabinet with the intent of putting a PC with MAME into it, and wiring up the micro-switched joysticks and buttons to a keyboard etc.
This was about 6 years ago, the machine is in pieces now awaiting me re-starting the project :)
The unit itself ( a 2-player NeoGeo unit, with “select game” button ) only cost me about 50 quid, and it had all the authentic ciggie burns etc on it.
it’s worth contacting your local amusement / arcade company, and asking them who supplies the units to them. It isn’t worth them fixing an old machine, and you will want a broken one anyways as you’ll have to break it anyways for putting in a PC with MAME.