One big draw of the Arcade-in-a-Box is the ability to plug the box into any TV via Composite or S-Video, although VGA is also an option, but we want to work with the lowest common denominator here. 640x480 is the best with those TV connections, although 800x600 will work pretty good as well. The game should be locked into one resolution.
If it has TV out then does it have a fixed refresh rate, and if so then what?