To cut a long story short: the cascading seniority succession in the HRE meant that I lost two duchies, because those old Salian bastards became emperor. Besides that, I also lost Swabia due to some inheritance mishap. So, I finally got to found the independence faction. Of course nobody joined, but at least the HRE transferred Swabia to me again. Yay. Because nobody joined I left the faction, and the king of Hungary founded the faction anew. While I was battling Sweden for a Bavarian county (really, Sweden...), the king of Hungary pressed his claim for independence. So I swiftly dispatched the Swedish deathstack, and faced the 30k HRE deathstack. With some luck and a reload I dispatched the stack with the help of a free company and 25k of my own troops.
So, here it is, the independent kingdom of Germany:
The HRE consists mainly of the kingdom of Bohemia now. That's funny, because Bohemia has been in every independence war except this one. I hope they fight the HRE soon, I don't want the HRE to pick on me. I'll see what happens if I start a new fight.