Thanks, this was a great suggestion. With the help of Wikipedia and IMDB, I've been able to hunt down some version of all of these on WorldCat. And it turns out two of them are actually available from Netflix -- one newly available (Docks of New York), and one under another title (The Enigma of Kaspar Hauser aka Every Man for Himself...).

These were mostly the tough cases: out-of-print compilations, silent movies, and foreign films.

I suspect I'll have to go to ILL for most of these, but at least I now have a WorldCat list I can hand a librarian.