As asked in the topic, why bother with periodic scanning of the music folder? After an initial scan, wouldn’t using Inotify be a much more elegant solution? To me, this situation sounds like exactly the type of thing Inotify was created for. You’d get instant response to files in the library changing, being deleted, whatever.
I have no idea what implementing Inotify would take. Though I cant imagine it being a huge hurdle, for all I know it could be completely unrealistic a proposal.