I've scoured every SCUMMVM archive I can find, archive.org, my own personal CD and floppy collections, general Googling...and still coming up short.
If you have (or know where to find) any of these demos (as DREAMM calls them), I'd be very grateful to know:
Indiana Jones and the Fate of Atlantis (Talkie)
Demo, English (UK White Label)
FOUND
Indiana Jones and the Fate of Atlantis
Demo, Prerelease
FOUND
Outlaws
v1.0 Demo, English (Multi-Player)
FOUND
Outlaws
v1.1 Demo, English (Multi-Player)
FOUND
Star Wars: Rebel Assault
CD-ROM Demo, English
[VERY generic name - all the demos were CD-ROM! The real difference is REBEL.EXE with a size of 226,750 bytes and a CRC-32 of d14ee2f4]
Sam & Max Hit the Road (DOTT Engine)
Demo, English (UK White Label)
FOUND
Sam & Max Hit the Road
Demo, English (CD)
FOUND
The Secret of Monkey Island (EGA)
Demo, English (alternate)
FOUND
Zak McKracken and the Alien Mindbenders (Enhanced)
Demo, English
FOUND