I recall seeing that this project was in the works back in the summertime, but haven't heard anything about it since. It would certainly come in handy for just about any Mame cab, and I'm hoping it exists!: a button mapping graphic display program, showing which cp buttons are active for, and what they do in, each particular game you select.
I know quite a bit our people were interested in this....If no one has done anything, I may have to draw up a 2d graphical cp, and change the button label text for each game, and use it instead of a marquee pic or something in a frontend. I was pretty sure that a database and program were underway tho....