The best examples which come immediately to mind are a Harlan Ellison script for a 1968 episode of the TV show Cimarron Strip, called A Knife in the Darkness, which explored the idea of Jack the Ripper relocating in the Old West.
And then there's a Richard Matheson novel called A Shadow on the Sun. Matheson was a specialist in horror who also wrote a considerable number of Westerns, so he was ideally situated to explore this specialised territory.
Well, sadly Richard Matheson is gone and Harlan Ellison largely inactive now, but a guy called A. Craig Zahler has fashioned an excellent film with the evocative title Bone Tomahawk (though I must admit that at first I thought it sounded like a porno comedy).
Without giving too much away, the premise of Bone Tomahawk is that a clan of highly primitive cave dwelling proto-Native Americans (referred to as "troglodytes") are discovered. They're ferocious and cannibalistic... and they've kidnapped the hero's wife. A posse sets off to rescue her, and a great deal of satisfying mayhem ensues.
The movie is a kind of cowboy take on The Hills Have Eyes... which is actually a great idea. Zahler does a commendable job of directing, but the strength really lies in his script. He's obviously done a lot of research, and his dialogue has an unerring sense of the period. Also, it's just good dialogue: "What's the time?" "It's about nine, but it feels like next week."
The characters are imaginatively conceived and well rounded, with a good cast to bring them to life, notably led by Kurt Russell as the sheriff, with Patrick Wilson as the aggrieved husband, Lili Simmons as his wife the local doctor and Matthew Fox as a gun-slinging dude. The music, by Jeff Herriott and Zahler is also memorable.
Zahler is a talent to watch. This film is extremely well made — and well worth checking out — assuming you don't have an aversion to westerns, or horror movies.
(Image credits: The posters are from Imp Awards.)