one problem with the region stuff is that there just isn't that much data to go off.
ie, nowhere does it say that pacman is a USA release.
what we need is a catver.ini type file that describes each game's country of origin/language.
so you're best off doing "no clones" and "playable" checkboxes and leave the region stuff out.
You could also save your working list as an XML file, then bring that XML file in as your main input. Then filter out japan games (since puckman says japan after it, but pacman doesn't say USA).
that might get you what you're looking for.