At the peak of my RSI I could barely hold a mouse, I switched to an adesso keyboard with touchpad in the center. It didn't cure it but it had an immediate and fairly lasting impact for the better. I'm so used to using a touchpad now I only use the mouse for PC games. See my other comment in here for the full story.
I just skimmed through carpal tunnel papers on pubmed, and found a surprising large amount of papers stating, that there is no correlation between keyboard use and the syndrome.
I find myself wondering if the studies you reference actually studied the effects of poor posture, or only the use of keyboards themselves.
I have found I'm much more prone to discomfort in my wrists when I am typing on my 10" netbook half-lying down on the couch with my shoulders 30-45 degrees out-of-line with the monitor.
I'm wondering this because I might be using the keyboard and touchpad in a different way than others, but naturally for me, as in: the path of least resistance.
For scrolling, my right forearm points at the touchpad in a 45 degree angle, my middle finger touches the pad and I move my whole hand at the wrist to scroll. So all the middle finger does is touch the pad and raise again.
I use my right index finger for pointing. To move the cursor up & down I do the same as for scrolling, only with my index finger. For left & right I do what would look like pushing a marble to move the cursor left and the reverse to move it to the right. So my index finger really points (mostly) to the left side (depending on forearm position) and expands in it's natural path.
Regarding heavy keyboard use you often hear about the emacs pinky when somebody over years strenuously used their pinky to hold the control key down.
Well, I've noticed that I press control with the finger nail of my pinky and alt with the nail of my thumb. I'm sure it's unusual and it looks a bit funny, but it's completely natural to me and not strenuous at all.
Though reading stories from people with syndrome makes me worrying :)