drf sent me a very short piece of an avi he was downloading... it looks like the beginning of "Aladdin and the King of Thieves" from a Japanese DVD. It's off-aspect (720x480), but it appears to be a 4:3 source. There's an interesting bumper at the beginning that says "Disney Video Premiere". I don't have enough video to look any further into it.

EDIT: Confirmed - it's a 4:3 source, NTSC native, and all the credits are in English. The audio is Japanese. I can use this video source, if no better ones turn up.