ComingSoon has an MP3 of Mark Hamill talking about Lucas' supposed plans for a sequel trilogy (this is his idea from the 80's - not now). That can be found on this page. I'm not sure if the link will still work, if not let me know and I can dig up my downloaded copy (maybe).
The Q&A sessions that the above comments were taken from is described at length in a 4 part text feature (with quotes). You can read that by going to part 1, part 2, part 3 and part 4. The first page links to an mp3 with comments from Lowry and Jim Ward on the film restoration and possible screenings respectively.
All of the above is regarding a Q&A session that took place shortly before the release of the 2004 DVDs. The mp3s are only extracts but perhaps some of the quoted text might be useful. For example, there's a bit towards the end where Kershner is asked if he was ever considered as director for ROTJ.
EDIT: I've just discovered that the links to the MP3s no longer work. If you'd like these mp3s (I know for certain I have the Mark Hamill one somewhere - not sure about the other one though) then please let me know and I'll start searching. Who knows, I may even find some other material that could be of some use.