It's been a while since I've watched the movie, but I seem to remember a part of Beethoven's 9th Symphony being played with synthesizers or the like in
A Clockwork Orange. But I could be completely wrong. I just remember lots of synthesizers and Beethoven.
I liked it though, whatever it was, but I'm pretty sure that it was just a transcription and not really a remix.
EDIT: I should really look more thoroughly for videos before posting. >.>
YouTube - A ClockWork Orange, Ultra Violence