Playlist and favourite persistence

I really like the Squeezebox and its ease of use. But there is one thing which bothers me and that's how playlist and favourites are handled.
Maybe some of you have other ways of working or there might be a plugin I am not aware of.

Generally what I would like to have:

- Playlists and favourites more or less to be independent of file locations and rescanning.
- To be able to store songs which I listen to a playlist when listening.

What do I mean with independent of file locations and rescanning:

- If I do a full rescan my playlist and favorits are usually gone.
- If I move files to another location it is gone from the playlist.

Generally I think about a construction where songs are added as favorite or playlist as a title/performer together with a hash.
As soon as a rescan is performed the playlist and favorites are kept up to date by adding missing songs based on this hash. Of course if the file is really missing it is marked as not available and the user has
to take some action. Calculating hashes would increase scanning time, but probably a hash on a subset of the file in combination with artist/title/playing time would be sufficient to uniquely identify the file.
Unfortunately I have never done anything with Perl, so I have to rely on others :(

Any suggestions / opinions / similar experiences ?