I've been trying to find some. Mainly trailers for fictional movies made from pieces of other movies (fake trailers), or trailers that make a movie look like a different genre (recut trailers). Here are some I've found
Mega Man fake trailer:
http://www.youtube.com/watch?v=D33b6FmT4Qw&playnext_from=TL&videos=J2qTin-lgYg
Thundercats fake trailer
http://www.youtube.com/watch?v=fb50GMmY5nk
Shining recut:
http://www.youtube.com/watch?v=sfout_rgPSA
Titanic: Two the Surface
http://www.youtube.com/watch?v=vD4OnHCRd_4
Scary Mary (Mary Poppins recut):
http://www.youtube.com/watch?v=2T5_0AGdFic
Brokeback to the Future:
http://www.youtube.com/watch?v=8uwuLxrv8jY