I believe ADM did a version of Aladdin and Doctor M did Little Mermaid - versions that utilise the new DVDs but fix up the changed audio and changed video respectively. I know transfers of the original versions as they appeared on home video might be better for purists... but I'd really try and track down an LD player or someone willing to capture LD stuff for you.

A long time ago I posted here on the forums about the Lion King LD set. This is the preservation I'd be most interested in. There are supplemental materials on the LDs that have not been released on DVD, you see. The "Making of" for example. Some legal trouble prevented them from including it on the Platinum/Masterpiece Edition. Plus, a lot of the Disney LDs (IIRC) have the subtle teaser poster images for their covers. I know Lion King doesn't, but it has a cool packaging design regardless.