I just had a little moodle with this ... I hadn't actually read your initial description closely enough and hadn't realised until now how the three lists worked together ... I had a play with some alternate interfaces but after refining it a few times I ended up coming back to your original design.
Anyhow, the upshot is that this functionality is now in CVS, just with a few tweaks at the code level (like putting all the SQL into a separate function).
Well done, Gustav! It has a good feel to it (fun!)