Check out the map of "Europe of the Peoples" in this article entitled
What Europe Will Look Like If Its Separatists Get Their Way. It's one possible way that nation states might reemerge from the ashes of a post-WWIII Europe.
http://io9.com/what-europe-will-look...eir-1636344143
On a side note, I find it kind of odd how in a world where globalization is supposed to be breaking down traditional borders that there is also a movement towards subdividing nation states by ethnicity. Instead of the world becoming less insular, it seems like it's becoming more insular. I pity geography students today- I remember taking map quizzes in junior high and high school and Europe alone had at least a dozen fewer countries back then.