Not a very significant contribution, I know, but I wonder whether this short clip from the Walker brothers may be the only "favorable" prequel parody I've ever seen.

It might be because the Vader scene in ROTS is actually a pretty damn good (up until the NOOOO, that is - all drama and impact flushed down the toilet in one moment), imo.

I'm guessing that many Emperor parodies will have some lines from the prequels, as well, seeing as he was fairly memorable and well-received (even by Plinkett).

EDIT: Oh SNAP, just remembered this one!
http://www.youtube.com/watch?v=eTkQ2mnn-ZE
Has quotes from both ROTJ and ROTS all mixed up, and it's pretty awesome :D

Heh, yea, seems like Palps had no problems to "transpire" all the way :)