Wanted to post a 30 min interview Christopher Nolan did with QT about The Hateful Eight, but it looks like it was removed from Youtube because it's gone from my view history and I can't find it again when I search for it. Anyway, in it he talked about how it was heavily inspired by The Thing and how the characters can't trust each other. He screened The Thing for the cast, with Kurt Russell being proud of his work.
He also talked about how it was inspired by the 60s western TV shows like Bonanza. Specifically, he was inspired by the cameos different actors such as William Shatner had on those shows. When they had a cameo appearance on the show, the audience wasn't told whether this was a good guy or a bad guy. So he thought "What if there were 8 such characters where no one knows who is the good guy or the bad guy" as a concept for this movie. Sounds interesting.