If there was a recent thread on this topic, I'm sorry.
I was going through the list of Common AH cliches, and I noticed one on German unification. Although it is probably inevitable for Germany to be united after a certain point, does it necessarily have to be a Prussian unification? Besides an Austrian unification, maybe the 1848 Revolutions lead to a liberal German state?
Anyway, your challenge is to come up with the most plausible United Germany you can without Prussia leading the charge. There is no limits to when the POD is, but I would prefer it to be as late as possible.