It's quite possible that those other missing films will be found; you never know what might be hiding in attics and basements and warehouses. For example, last year Image/Milestone Video released the Fatty Arbuckle-Buster Keaton two-reeler "The Cook," which had been considered lost for decades. It's truly a great discovery, since the acrobatic slapstick antics of Fatty, Buster, and Al St. John are jaw-dropping and hilarious at the same time. Luke the dog is a remarkable "actor," too.
Two partial prints were found, one in Norway and one in Holland, and from those, a team of film historians and technicians was able to put together a virtually complete print— from what I can tell just by watching it, it looks like it's only missing some brief parts from a couple of scenes. Not only that, but the visual quality of most of the film is surprisingly clear.
I'd like to see not only the "Lost Stooges," but the missing half-reel of Laurel & Hardy's "Battle of the Century" (directed by Clyde Bruckman). The current video release fills in the gaps with stills and the typed script, which is the best that could be done, and at least the monumental pie fight at the end is intact. The first-reel boxing sequence is a definite influence on "Punch Drunks," although "Canvasback Clump" Stanley has no magical "Pop Goes The Weasel" (or anything else) to save him from the heavyweight champ.
Another amazing find from that period, in sound recordings, is one of the earliest experiments with recording music in stereo— from 1932— and who'd have ever thought that stereo went as far back as 1932? But it does.
In the early 30's, RCA Victor was experimenting with a longer-playing, microgroove record to replace their 10" and 12" 78's. This was especially important for making classical records— since at the time, if you wanted a recording of a long work like a symphony or an opera or a piano concerto, what you bought was literally an "album" (like a large photo album) that contained as many as half a dozen 12" 78's, as heavy and thick as china dinner plates (and just as fragile).
After every four minutes or so, the listener had to get up and change the record, sometimes in the middle of a movement. So, Victor's engineers came up with an early EP (about seven minutes per side), but technical problems with disc-pressing materials along with the economic climate of the Depression led to these records never being mass-marketed.
Anyway, back in the 1980's, two record collectors noticed that their copies of two experimental 10" Victor EP's by the Duke Ellington Orchestra sounded slightly different; like for example, on one, the drum part was loud and the trumpet part was soft, and the other copy was just the reverse. On a hunch, they recorded them side-by-side on two-track audio tape, and presto! Real stereo, from 1932! These two recordings were remastered and issued on a CD, which is now (unfortunately) out of print.
I've rambled on here for a bit, but I think that's an amazing story, and there's a future Pilsner's Picks segment that I hadn't thought of before, since I do happen to have the CD.
So, you never do know what kind of rare old material will turn up, or where it might come from!