I remember seeing a map many years ago that had the premise of the Confederation of the Rhine not only surviving, but growing to unite Germany.
It was interesting - I believe the idea was that Napoleon's brand of nationalism took root in the Rhine, and by the 20th Century "Germany" was dominant in Europe, even over France, because the idea of "German nationalism" was popular in the confederation. I don't now how plausible it was, it was a long time ago before AH.com became far more strict about plausibility, but it was a fun and subversive scenario.