I'm not too sure of the technical jargon, but I've seen a half a dozen films projected at IMAX theatres that were not specifically prepared for the format. For example, I saw the original Star Wars & Empire, Raiders, and a couple of others at an IMAX theatre, but they were not necessarily taking advantage of the format - basically the theatre was projecting 35mm prints onto the giant screen.
This is unlike AOTC which was specifically edited and formatted for the IMAX experience (for better or for worse). The cut was tight - real tight. It removed a lot of the things which people found annoying.
Like I said, replicating it would be difficult. I would not even care if it wasn't the correct aspect ratio, as long as the cut and dialog were consistent with the IMAX version.
There just has to be a boot of this somewhere - c'mon, this is Star Wars we're talking about. I can't believe someone out there doesn't have a copy.
There are a few sites which document the alterations, but I couldn't dig up the technical nitty gritty stuff - ie: where the cuts occur exactly at which frame and so on...
I would imagine to do an accurate job you would need three things.
I doubt this will ever happen, but it would be nice...