I started tinkering around with a 6 in one edit way back when. Actually before Sith had even come out. Hoping to do it in 3hrs 59 minutes.
The OT is definitely easier to scale down, because there simply isn't enough stuff. But I have been hung up on the two death star things.
How to have one death star, still have Luke as a pilot. (not completely necessary that he be the one to blow it up) and still have Luke/Vader/Palps sequence work.
Its tricky. And moreso, I really would want to do it without actually changing too much plot. I agree that they could go straight to Hoth after the DS escape with the princess. I actually think they could not even go to the death star. They could get tractor beamed into the Star Destroyer that Vader is still on and is holding Leia Prisoner. Which frankly makes sense. I never liked that Vader is so hard up to get those plans but just takes off back to the DS and trusts loser troops to find them. Maybe he is still nearby on his SD.
One thing I have already done:
Falcon takes off from Hoth into heavy Star Destroyer traffic. Immediately cut to frontal attack and then hiding on the back. Then I edited in their conversation about Bespin and a romance scenes from the cave as if they happened while clinging to the back of the ship. Then they go to Bespin as if nothing is wrong with the Hyperdrive.
My ultimate dream would be to have the Luke/Vader/Palp sequence some how cut out..(I believe rotoscope is the method, though I admit to not knowing how to do that) and added to Emperor's thrown room on Coruscant, which I feel is where it SHOULD be. Kinda thought it would be awesome if the first Vader/Luke conversation about Anakin took place in the Jedi Temple ruins. Thats a whole other thing of course.