I'm no expert at video editing or rotoscopping, but I figure you could probably cobble together enough material to construct a believable scene for the Emperor's arrival in the beginning of RotJ using shots from ESB and a bit of special effects.

I put together this little picture to show what I'm thinking:

http://img234.imageshack.us/img234/8290/proposal5oa.jpg

Frame 1: RoTJ opening crawl pans down to...
Frame 2: ...flopped establishing shot of SSD & fleet from ESB
Frame 3: shot of SSD & fleet approaching Hoth with the DSII rotoscopped over the planet
Frame 4: another flopped ESB shot with a shuttle (taken from later in RotJ when Han & the gang are flying it) rotoscopped in
Frames 5&6: return to normal RotJ Emperor's arrival scene

If this kind of editing is completely unfeasible, then nevermind.