I've played a fangame called Pokemon Glazed, which is an emulator game btw, and it sort of mixed the pokemon world and the real world together, though there were only a few moments where this occured. It was a nice concept, but the creator didn't fully implement it in a way that you actually walk through a real world, only bits and pieces of it(like a street you would find in the real world, with cars passing by, is on of the parts you are in the human world).
If you don't know the game, I highly recommand playing it, since it's actually quite long, and I've not even finished the game yet
Hope this helps in your search ^^
P.S. I would love to see a fangame that meshes the worlds together, and preferably something that makes it more realistic would be cool(like people from PETA being the enemy, like team Rocket, or that the "gym leaders" are the presidents/kings/whatever of countries, and you have to battle them)