I also stumbled upon this yesterday, for making the rest of OS X more like emacs (or VI). OS X already has emacs keybindings for all text areas, but it is missing some functionality (backward|forward-word). OS X has a concept called input managers, which allow you to plumb in your own custom behaviour.
http://www.hcs.harvard.edu/~jrus/Site/Cocoa%20Text%20System....