It would need to be somewhere between the CE3K and Blade Runner sets in terms of size. You would need two discs per film, you couldn't seamlessly branch both versions onto the same disc since there are at least a hundred differences between the two. Then there's the color differences that we've all gone over at length. So one disc for the original version and one disc for the latest version would be just fine. If they really wanted to go all out, they could wedge a third disc in between the other two with the '97 version.

By the way, despite all this speculation of there being even further changes, I have a feeling the '04 versions are the end of the line. Getting Lowry to scrub the picture and adding TPM Jabba, Temuera's voice, Ian and Hayden are really all there is to it. I dunno, I just think that if Lucas was going to go ahead and make those additional changes back in '04 with Episode III (the final prequel) right around the corner, he would've made all of them at that time. The same goes for the dvd versions of AOTC and ROTS. TPM is the only one I'm still curious about.