ok then listen this one
what if the databases were managed as modules? there is a master database that comes with the official releases and it is unmodifiable and then slaves/modular ones in wich you can store your additional games or else the master one is modyfiable but you cannot add games to it?
also you could release multiple masters this way for each additional official release, and each one has new games' configurations, so for instance, instead of download the 4 CD release of GBC64 (when it will be available) you would download only additional content (1/4 of the stuff)