Finally, I got the coin-up code finished enough to work in-game. I ran some tests on it today and the only issue I have now is that less than 2% of the coins inserted don't trigger the coin-up properly and the coin-up sfx only plays on levels where it's used.
I'll probably make a quick video at some point today to show the coin-up working on real hardware. (i.e. my SuperFamicade setup.) My rig is a bit jank-tastic at the moment since I still need to build the cabinet itself.
The final cabinet will closely match the look of the Nintendo Playchoice cabinet. The main difference is that I will be using white vinyl with custom side-art graphics.