I was reading The Guardian today and spotted this article on a guy who bought a random film reel on ebay for £3.20 which turned out to be an unseen short film by Charlie Chaplin. Surely something to put on the IMDB trivia page, when it eventually gets one.
I guess one of the most famous stories is of Carl Theodor Dreyer's The Passion of Joan of Arc turning up at a mental institution in Norway in the eighties -- I shudder to think that that particular classic could have disappeared. It does make you think though; how many lost or unseen classics are out there somewhere? Arts heritage has definitely gotten better of late but damage has been done. Let's hope there are more spectacular finds to be had.