I'm confused--would this be stage or film? I've always wanted Fincher to do a musical (he pursued Evita for a while,) since the best of his music video work seems to show he really would be a good fit, and he's a big fanatic of the genre.
Waiting to hear what "His Name Was Robert Paulson" will sound like, because you just know that will be a song.
On a serious note, though, I think it would be nice if they manage to work in some stuff from the novel that didn't make it to the movie. The movie cleaves pretty close to the source for most of the run-time, but goes off the rails toward the end. The movie's ending is satisfying, I suppose, but it's a cliched upbeat Hollywood tweak that maybe the musical won't need, especially in this style and with this creative team involved.
SPOILERS WITHIN
In the book, Tyler Durden's demolition plan fails; the narrator shoots himself to escape the fictitious Tyler and ends up in an asylum, which he mistakes for heaven. Sinister suggestions reveal that Project Mayhem will continue, now out of his control. About as bleak as you can get, but overall it's quite fitting with the dark and twisted nature of the novel. But in the movie? We close on the sight of buildings collapsing as the now mentally sound narrator and his love interest, Marla, hold hands. They beat the system and fell in love.
END SPOILERS
Also, am I the only one hoping they bring back Meat Loaf, voice or no voice?