I'm putting in this plug all over the place, but I have become fairly convinced that the best prequel fan edits would change Ep II into Ep I, create a feature length story from the Clone Wars series for Ep II, and then edit Ep III. Elements from TPM could be retained for the new Ep I, such as Darth Maul, perhaps even starting as Topher Grace did with the Maul/Kenobi/Ginn battle, and then reintroducing him as the primary villain for Ep II whilst giving more background to Grievous. I know that there would be a jarring change in styles from live action in Ep I to CGI in Ep II and then back in Ep III, but I think it could really make a more congruent story. Since the series may be wrapping up fairly soon, I have high hopes that someone would consider that route.