[OP of "Is there an argument for striking down marital rape prohibitions as unconstitutional?"]
Don't they amount to a taking of property without due process of law? It's like if the government were to say, "That cannabis you have in your pocket is no longer your property, because we've banned it." If the government says you can't rape your wife, then they've basically taken away your right to use your property as you see fit.
But that's the problem with a general police power. It basically means you have no rights. Police power (United States constitutional law) - Wikipedia
What if the government wants to take your house, just because? They have many ways to do it. They can say, "We're seizing it under eminent domain." They can say, "We're imposing a heavy tax on houses that meet certain criteria (which your house just happens to meet)." Or they can say, "We're condemning your house as unsafe." Etc., etc.