I think I kind of remember seeing that on a poster a long time ago. It is pretty cool how it all connects.
While Unova and Kanto region are inspired on real cities (which I also find pretty cool) I don't see why they couldn't belong to the same world in the Pokémon Franchise.
They were too big to implement, thus they were removed from the original 4 regions and crafted into their own thing, thus making the who idea of "Importing Pokémon" a legitament thing.