There's a new article (autotranslation linked) on the bassoforte. It has a bit of mention of a collaboration with TU Dresden, and a mild notice by a player about the new keywork (there are no open toneholes, if I understand right). Quite interesting. Even better, there's a video, with sound! I had to skip the German interview, but there's some audio of the instrument at the beginning and end. To my ear, it sounds a bit blatty, but no doubt that will just help it "keep up with the tuba', as Guntram Wolf says.