It's been years since I have played with one, but I am pretty sure the classic Taito cabinet was about as close as it came to a commercial machine that you could disassemble and reassemble easily. They had no timber frame, just mostly corner brace brackets and furring strips. It was the same concept as Jimo's, but brackets and furring instead of the frame. You could see carriage bolt heads on the sides, and I agree with Jimbo that the carriage bolts don't detract, but I suppose you could sink your bolts in and cover the hole with bondo and the bolts would stay in place.
The only thing I can think of that wouldn't be at a hardware store would be torque washers. Those should make the job easier if you want carriage bolts in wood. Like a regular washer, but the square neck of the bolt will catch on these to keep from spinning and easier to tighten:

Then on the inside, have the bolts go through a couple sets of these as the main backbone, and smaller brackets elsewhere. Take off the nuts off your brackets and it should all come apart.

Have your CP box snap on and off from the inside easily with some control panel latches.
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