hey, a great idea.
i was thinking, there is no reason with a little care, u couldnt make another small hole in the cabinet in the appropriate position and keep the tournament button as well as adding the volume switch as well, if u wanted to.
might buy one and try it out, with the idea of making it work whilst keeping the tournament button cause I set up the tournament on my new Sterns to get all the extra cool dmd annimations, and its a fun way to have a home competition. I am sure i could keep the tournament button and still make the volume button work with a slight fiddle. thanks for the link.