Anyone feel like writing an app to allow N900 to function as a bluetooth hardware keyboard for the N9?

I'm imagining that a lot of us will be carrying around both devices for a while, until the N90 'matures' and offers a similar range of functionality and various wrinkles are ironed out. Wouldn't it be handy, and kinda cool, to be able to use N900 to type text into N9? Would this be hard to implement?