The Merchant of Venice (unfinished film) (1969)
The Merchant of Venice is frequently cited as an "unfinished film" directed by Orson Welles and based on William Shakespeare's play of the same name. It was actually completed, but is better described as a partially lost film. Welles played the role of Shylock in addition to producing and directing the film as well as writing the adaptation. Charles Gray featured as Antonio and Irina Maleeva as Jessica. Further cast members were Dorian Bond, Bill Cronshaw, Mauro Bonnani and Nina Palinkas. (Bonnani was not a professional actor, but an editor who was then working on Welles's Don Quixote, while Palinkas was the younger sister of Oja Kodar, whose real name was Olga Palinkas). Differing sources give the film's running time as between 30 and 40 minutes.
More at Wikipedia.