Is it possible? A USB PC Keyboard (not a MIDI keyboard) that can be routed to MIDI data?

Maybe this post can help:

http://puredata.hurleur.com/sujet-2065-joystick-midi-patch

I'm still experiencing problems with the technique. The devices still behave like the original device ( my modded mouse (http://www.zerolmzero.be/1.1/2008/08/hid-mouse-stompbox/) is still a mouse sending midi at the same time. But I still need to find a way to kill the original mouse functions).

Another forum which I'm following to find the answers:
http://djtechtools.com/forum/showthread.php?t=889

Thanks, and your problem makes sense (and I can see how it'd be quite annoying).