http://lostepisodes.fateback.com/prequels/

Just found this website. Not sure exactly how reliable their sources are, but there is quite a whelp of information and speculation of the prequels dating back as far as pre-ROTJ. In the "Clone Wars" section, there is a rather long article written by a fan speculating what the story of episodes 1-3 would be that, while it may not be too useful for coming up with a story, it certainly is interesting to see the backstory from the point of view of a pre-return of the jedi mind. There's actually an interesting theory about how Darth Vader and the then unnamed Skywalker actually were two people, but Vader was a clone of Skywalker who went on to "betray and murder" Skywalker. So when Darth Vader reveals to Luke that "I am your father." He is telling the truth.... from a certain point of view. That theory just stood out for me and, while it kind of negates the idea of redemption present in Return of the Jedi as well as Ben's speech to Luke, it's still a pretty cool thought nonetheless.