Sadly, a naive approach as outlined doesn't really work for per-caller ringtones. See
http://talk.maemo.org/showpost.php?p...6&postcount=12 for gory details. It maybe could be made to work if there's some way of forcing a sound file to be played while the phone is "ringing" in silent profile mode.

Not tried rejecting calls, though. I suspect that would work fine.