Don't forget the commentaries from the 1993 laserdisc set. Even though they only talked during 50% of the movies, I found them more interesting than the 2004 ones.

I'd also like to see an ultimate box set have a lot of features or tributes to the fans and star wars fandom in general. Maybe includes some of the better spoofs and parodies (like Troops) if possible.

There aren't many film franchises where it could be justified having over 3-4 discs of bonus materials but Star Wars is one of them.