my god you wrote that up about as fast as i can read it lol. Lemme get home and read it again... but from the looks of it it seems like the structure of rr's playlist management would have to change for this to be a reality. Some of the stuff can be done with plugins, but having to do all the legwork with custom indicators/labels/playlists would get pretty messy.
That bein said i'm gonna take a look at what we'd need to do . I'm sure when guino reads it he'll shed some light on it too.