I can't say this works well or not but I started searching this topic and found this right away: http://www.lightio.com
- you don't even have to touch the keys.
I have a MS Ergonomic keyboard for several years, btw, and it's nice. (Model 4000). The 'gull wing' makes for easier typing, for me, but what I think is the most important feature for reducing stress and pain is the wrist-rest.