keyboard behavior change

I have changed drivers/tty/vt/keyboard.c to allow me to use my return key (or any other key) as a control key if pressed with another key or simply as the return key when pressed and released. This only works in virtual consoles. I would like to figure out where to move this code to make it work all the way up, so it will work in virtual consoles, X11 apps, and for all keyboards. I want to make it appear that 'keyboards' just work this way. Anyone have any feedback to where to do something like this? I have considered doing it with X, but I also would like it to work in virtual consoles as well as X.