Clean audio dir function for Ardour
Cakewalk Sonar has a useful feature that analyses projects, scans the audio data dir, and removes (if you approve this action) all unused audio clips. This keeps unused files from eventually taking up tons of space, as when projects move along, lots of clips get rejected but linger in the audio data dir.
This would be very useful for Ardour, too. I'm sure in addition to delete, you could make move an option and have the user select the destination to remove unused clips to.