Some do - like the Cinesphere at Ontario Place in Toronto. They tend (like I said above) to show things like 'The Matrix' blown up from a 35mm print, rather than an actual formatted IMAX film.

So, to arrange a screening of the correct IMAX cut of AOTC would be night on impossible, I would imagine.

The best possible case scenario would be to get ahold of either someone who was associated with editing the film down, or finding someone who saw it a bunch of times and can recollect the alterations.

Then, as Hal said, he can create an edit "in the spirit" of the IMAX cut...