I find this a truly interesting thread, fascinated as I am with Williams' 'collaborations' with dead composers, and will check out the 'borrowings' mentioned. The first time I listened to Parade of the Ewoks I immediately got the sense that it was almost composed on top of Prokofiev's March from his opera Love for Three Oranges. And The Dune Sea of Tatooine from A New Hope is more or less lifted from the beginning of the second part of Stravinsky's Sacre. But perhaps this has long been common knowledge.

I wonder whether anyone has DETAILED information about what music made up Lucas' original temp track (I mean specific cues).