Mike, I am not sure how much Kevlar would be an improvement over anything else. As far as I know Kevlar is mainly for impact or tear resistance, which you don't really get in a board. I would personally stick with carbon fiber or fiberglass. A carbon board would be pretty sick, but it's damn expensive. Check out my group's website, we are doing some stuff that is pretty similar to your idea. www.enterprise.mtu.edu/boardsports
Let us all know how it goes for you!
- Andrew Brinks