Here's a toughie.

Watched a film that I believe came out after 2000 which was set either in the West or during the American Civil War (or both); began by the group of protagonists robbing a bank and fleeing to an abandoned farm estate.

A few strange things proceeded to happen, but what I enjoyed most was the ending, which depicted the protagonists running from the estate through a corn field, and after being shot down by police officers, it revealed that they were actually some kind of hairless dog, somehow being transformed during their stay at the estate.

I could have sworn the movie was called 'Dead Ringers,' but that is the name of a much older film which has nothing to do with it.