Rankin/Bass Cels

Hi,
Im looking for some Rankin/Bass cels. They produced an animated movie based on J.R.R. Tolkien's book The Hobbit. Rankin/Bass also produced the movie: The Return of the King, which is based on the third book of the Trillogy.
These are different form the Tolkien-related movie done by Ralph Bakshi. Rankin/Bass also did The Flight of the Dragons which I am also looking for. Anyone has any leads let me know.
Thanks
Frank