The ringtones are polyphonic for the 7650, ive had one for a while now. U can upload midi file from your computer if u hav an infra red port, not sure if u can do it via blue tooth (if your comp is equipped with it).
Some website that offer polyphonic ringtones (midi files)are having some problems with 7650s' so far but it shud b sorted soon (so theyve told me anyway!)