This is a scenario I haven't seen discussed yet. So AHers, your mission, should you choose to accept it, is to make Austria unite a German nation sometime in the 19th century, preferably leaving a surviving Prussia separate but Grossdeutschland is an option as well. POD can be anywhere from the late 18th century onward.
Were are these Germany's borders? Is the Hapsburg monarchy constitutional now? What do they do with Hungary and the lands beyond it? How do the other great powers react to this new player? Who's going to be fighting who in the inevitable(?) Great War?