Other than Project N955, the nascent iControlPad2 game-controller/keyboard combo project shows promise in this regard (especially since the original iControlPad is already known to work well with the N9 thanks to the work of this community).

I especially like their solution for keeping the controller out of the way when not needed...

http://www.youtube.com/watch?v=l3uKuZq7yBM


By the way, they've gone the Kickstarter route:

http://www.kickstarter.com/projects/...rce-controller