As I sit on a bus on my way to Boston for a convention, I'm reading a bit about Germany in the 1860s. One thing which I just came across is that in 1870, the pro-Prussian cabinet in Munich was replaced with one dominated by the Patriot Party, which was led by particularists opposed to continued German centralization.
I don't think Bismack's motives asre as clear cut as susano thinks; it's not clear to me that Bismarck didn't want a united Germany, ultimately, even if he called it an "unripe fruit" in the 1860s.
But even in 1871, it was a very federal state. Without the Franco-Prussian War, what would it look like?