I believe that a transfer of the Japanese LD and then substituting the video where possible with the DVD quality video might be worthwhile. I'm not sure if you're aware, but the Japanese LD has a much better sound mix than the DVD. This would also be another worthwhile reason to preserve the LD. I stand as one who would like to see a composite DVD that uses DVD video (except in cases where the LD has additional material not on the DVD) and the LD's soundmix for the audio. I still think this might be a bit too much on the "bootleg" side to talk about though. :/

As for Episode II, I believe someone around here has a bootleg of the theatrical cut, you should try Rikter.

And, finally, Episode III... I was under the impression that ROTS had no changes made for the DVD release, and to be honest, such a minute change does seem a bit of a stretch from "preservation" to "bootleg".