In reply to:
In theory, it should be possible to figure this out from the scratch partition, no need to use FIDs to do it.
That's true. But it would be much more convenient for the client tools (emptool, emplode, jemplode, and the Hijack Web interface) if it appeared as just another playlist - no need for special-case code with a different protocol, and no need to duplicate the work in all of the clients.
A Hijack WWW-based UI for viewing/manipulating the running-order and bookmarks would be a useful halfway-house, though, and I think the simplest to implement (as it's on the player and thus has direct access to the disks). Now I only Wish that I had the time and skill to do it myself - I've just started a new job (same company) so I'm busy learning all the new stuff I need. (On the good side, it is all Unix and X11, so at least I feel at home.)