Mice/trackballs...meh
Having started to get nasty Carpel tunnel some years back, I switched to trying to use a trackball. Nah. Just ended up with a sprained thumb.
For quite a while now I've been using various incarnations of the Anker/Perixx vertical mouse. Basically a different shape so the hand is vertical, and larger than a standard mouse, but otherwise you still move it around. Very comfortable. No carpal probs at all now. They're about £15 from You-kno-who, and tend to conk out after 2-3 years, but well worth trying.