It would probably be possible to come up with something pretty close, but recreating it exactly is out of the question without the right sources to compare it to. I definitely don't trust the lists of differences out on the internet--I've seen numerous lists of changes in audio for ANH that I know are inaccurate, and that is the better documented film at that.
The claim that the SE mix of ESB is based on the 70mm version has been put forth many times--it seems to me that someone said it at some point and then many other people took it as gospel that it was the case, propagating the rumour. While possible, I think it's important to remember that this claim is unsubstantiated until proven with an actual source. Keep in mind that it is, after all, the SE--many things about the films were being altered according to the whims of those in charge, and being faithful to how it had been was hardly their priority.
From an audio standpoint, such a reconstruction would be best derived from the Definitive Collection soundtrack, since it is the best-sounding mix of the original film available, and then subsequent edits from other sources would fill in whatever changes were necessary. How much of it would be possible while maintaining sound quality and faithfulness to the actual mix being emulated is impossible to say, since this is all just speculation at this point. I'm sort of inclined to believe that the '93 Empire is actually closer to the 70mm version than might be suspected at first glance; but I don't have anything to back it up, other than a feeling that the mysteriously missing snowspeeder crash sound could be connected, since they were using early generation sources to make the DC version.
For my part, as a follow-up to the success of recreating the Star Wars 70mm, I'm going to make a new 5.1 for Empire, which will use the 1993 mix combined with a few segments of the SE to 'correct' the choppy music editing, and the special edition LFE channel for the low end. This can't exactly be called an accurate 70mm recreation, since we don't know for sure what it sounded like, but it could possibly be considered an approximation of what it may have been, if you will. In any case it should sound great. :)