I ended up buying the low wunderlich seat for my F800gs.
I have made some requests for experiences in this thread without feedback, so I would like to share my first thoughts about this seat, maybe more people will be interested in firmer seats after "Corbingate".
Today was the first real spring day in Denmark, and I went for a good long ride.
I am very happy about it. It looks good and the quality and fitting also seems very good.
It is very firm, but kind of "gel like". For me the ergonomics are much better than the stock seat.
The only downside I can think about, is that you have to reuse the rubber spacers from the stock seat.
Your butt does also not slide easy over the back part of the seat for hard core decending, because of the seat profile, but it is possible to change the riding possition a couple of inches forwards and backwards during normal riding.