If you're interested in pursuing something like this I think you really need to find a problem that is big and important enough for your average developer to agree that the cost is worth it. Being able to use insecure networks safely turned out to be important enough that we're making strides to TLS, though with a lot of struggle, what problem is as important as that for people to start thinking of doing this much work? And is there any way to scope it down to be less work?
Maybe you could convince people that we need to sign ads so that it's not so trivial to deploy exploit kits inside ads, but we're largely solving that by making exploits more expensive, rather than solving ad integrity, so the gain on this is smaller than it would have been a decade ago.