Hi!
The Advanced Launcher is no longer developed from that what I know. I think that adding missing mGalaxy features to it (category and player num. filtering, game infos, flexible switching between systems, etc.) would be the best idea. There is no need to start from scratch. The latest Adv. Launcher version is too buggy for me, it lags every time you launch a game. So I would suggest starting with a fork of older revision. The other option - ROM Collection Browser, great but lags when you quit MAME.
Best Regards!