I vaguely recall reading a published short story of an ATL where beethoven finished his 10th Syumphony and it galvanized German nationalism, resulting in an earlier German unification. Sorry, I can't recall title, author or much in the way of detail.
I, too, have read it. It leads to a triumphalist German nationalism in a Grossdeutschland, ie including Austria in ?1848?. Im thinking it was by a major author, but I cant remember who, or where i read it. I googled several things i thought might help, but none did. Sorry.