Oh wow, that looks like a great effort.
Drool at this:
These enhancements go beyond the original functionality that the device provides under Cubase but I found them very handy when working with the CC121:
Pressing the mute and the monitor button at the same time will swap the functionality of the volume fader and the pan encoder so the fader will control the panorama of a channel and the encoder will control the volume. This will make the automation of pan data much easier.
Pressing the write and the VSTi button at the same time will disable and enable the motorfader. This is usefull in many recording and mixing situations where the sound of the moving fader is disturbing. This shortcut is much easier as plugging the wall wart in and out every time to shut up the fader.
Come on Steinberg, Reaper can now use the cc121 better than Cubase, fix that!