i am using PiMAME 0.7.6 and it seems to work very well - good job :)
But i have a few questions:
1) Is it possible to configure custom input buttons and joysticks over the GPIO interface (2 pins for every button)?
2) if i start "puckman" with AdvanceMAME it is always in the "Free Play" mode. I can change the settings via TAB -> Dip switches -> Coinage. I want to keep the coin option. Every time i restart AdvanceMAME it is set back to Free Play.
You can turn off free play in the /home/pi/.advance/advmame.cfg file.
It is possible to use gpiokeys as an input and use a button connected to the gpio pins to trigger a coin. I don't have any writes up on how to do that, but yes it is possible.