Some people may say that a 448kbps for a mono DD track is overkill but I agree with you Silver, Walter Murch's groundbreaking sound design is half the experience of this film. I might even do an encode with the uncompressed PCM for you and those who want that.
I'm not really sure about stills, the trailer and the "lost" SEN scene, it sure would've been nice with an additional disc of extras but right now I feel that I want this as uncomplicated as possible so we can get this film out to people as soon as possible with all the time this have taken me. I actually lost most of my additional THX material I had in my HD crash, think I still have the radio spots though.
The SEN scene Puggo sent me is safe, I don't know, maybe his planned transfer will do? I hope my answer doesn't disappoint you too much, but I just want this done as soon as possible even though it was me who originally suggested many of those extras. Maybe someone else could help make a bonus feature DVD to accompany the main feature disc? that would certainly make things easier for me.
Nice idea about the '78 trailer, although I think I still would like to have the original as well even though the quality leaves a lot to be desired.