For students of cinema, several films-that-were-never-made have been the subject of articles, books, and documentaries. Historians enjoy imagining just what movie delights almost happened, that were stopped by different circumstances, often budgetary. I recall seeing production art for Willis O’Brien’s teaming of titans in “King Kong Meets Frankenstein”. Before George Pal produced the definitive big screen version, Ray Harryhausen shot test footage for a proposed “War of the Worlds”. And animation buffs have wondered at the pencil test sequences Looney Tunes wildman Bob Clampett whipped up to try to sell MGM on a cartoon short series based on “John Carter of Mars”. And in this “what if” study, there would need to be a sizable sidebar on the unfilmed works of Orson Welles. Years before Coppola, Welles tried to adapt Conrad’s “Heart of Darkness” for the movies along with comics’ “Batman” and “Don Quixote” (Terry Gilliam’s...