This is a really old post, but I stumbled across it on Google and couldn't resist making a few comments.
A heated or warm mouse pad is a great idea. My sister invented a mouse hand warmer blanket pouch and I put a warming mouse pad inside of it. It really makes a difference in the winter.
My hands get really freezing cold so I also use a mouse that warms up, too. Don't laugh. It really makes a difference.
The USB warming devices use infrared heat which has healing effects. You can read about the healing effects of infrared heat at http://www.valuerays.com
I want to find a keyboard heater. I think the other hand needs some warmth, too. If you find a warm keyboard available in the USA please post the link here.
Thanks, Bernie InCogNEATO!