Here's an idea, as a special feature on the bluray, why not include a fan-made documentary about the film? Jamie Benning's "Star Wars Begins" filmumentary would be a perfect fit, I think:

It's feature-length, and the flow follows the movie itself, but putting in behind the scenes footage, on-set audio, behind-the-scenes shots, pre-effects shots, commentary from cast/crew, deleted scenes (like Biggs' original scenes), captions discussing behind-the-scenes facts, all sorts of good stuff. It's fantastic.

It's 1.4GB for the version that's on Vimeo (you can download the original 720x576 m4v from there). Could Jamie Benning be contacted to get permission to include his documentary on the bluray? It's one of the best documentaries on Star Wars I've ever seen, second only perhaps to Empire of Dreams.