Nasrudin (partially found early prototype for "The Thief and The Cobbler"; early 1970s)
From The Lost Media Wiki
Nasrudin is an early title of the film that would become The Thief and the Cobbler, created by Richard Williams. The film would have been based off of a series of books about the tales of Mulla Nasrudin written by Idries Shah, which Williams illustrated.
By 1972, three hours of footage were completed, but Williams had a falling out with the Shah and abandoned the project. The Shah family gained the rights to Williams's illustrations, but the completed animation has never been released.
All that has resurfaced is a short clip of the film from a documentary called One Pair of Eyes. The whereabouts of the original film are unknown, and little else about the film is known.