Prussia was a militaristic state on the wane, no way could a kingdom split in two like it was have managed to achieve unity. Bavaria would later develop a good industrial base but without German unity would this have happened in the same way? Saxony was a faded power and Hannover without Britain a provincial one.
With the revolution failing, no way can I see a united Germany coming from any of these. Another revolution? Maybe if the Rhineland breaks away from Prussia and asserts its Westphalian identity?
Perhaps they even invite a Bonaparte in to unite Germany under their rule?
Best Regards
Grey Wolf