For me, the keyboard is not as big a deal as the mouse, or lack of.
You see, i had much more strain on my right hand with my mouse. Got real bad. I got a trackball and have never looked back.
If you try a trackball for a month you will never go back to a mouse. Its only a mouse upside down but works better, faster, and easier on the hand, fingers, and wrist too!
YMMV and this is about keyboards, but, again, i bet if you kept your keyboard and switched to a trackball you might be surprised at the results.
Unless you are a dos person and use the keyboard almost exclusively.