This is proving to be very hard. I can't think of anything that would work. Every opposite or unexpected mix I can think of is just OK... I think that's the point Butcher was making anyway, that you can make a great story out of any crazy combination of things.
So each topic I'm trying to match just seems alright. If I can imagine a story in it, it can't be that unexpected or unordinary.
So would dinosaurs and pirates work? Dinosaurs and mercenaries? See, my problem is that it sounds perfectly fine. A guy already managed to publish dinosaurs and knights, so how am I making anything original out of that? Fantasy is arguably the one place where its harder to find truly incompatible/opposits themes that haven't been mashed together.