From Filmthreat.com:
In celebrating the most intriguing unfinished films ever made (or never made, if you prefer), certain ground rules need to be considered. First, a film cannot be completed belatedly – this cancels such noteworthy unfinished works as Erich Von Stroheim’s “Queen Kelly,” Sergei Eisenstein’s “Que Viva Mexico” and Orson Welles’ “It’s All True” and “Don Quixote.” Those films saw some degree of completion, in one form or another, and found their way into commercial release.
(via Begging to Differ)