I did notice this on a few occasions: trailers that show scenes not in the movie, or scenes from alternate angles.
-In a Colt's Shadow (Japanese SPO DVD): 2 alternate scenes from the end duel
-A Coffin for the Sheriff (Japanese SPO DVD): longer intro (showing the wagon ambush)
-Bullet for the General (or was it Run Man Run?): scene where they are led in front of the federale captain and shoot their way out: alternate angles.
It's not unusual for trailers to have footage different from the final product, but anyway, anybody have some comment or some more examples?