No I don't. I belong to a large woodworking club here in Southern California. Ever other month we have a challenge. Not a competition, but rather a way to get the members to do something they otherwise wouldn't do. We had a challenge to build a musical instrument out of wood or something that makes noise. I chose the thumb piano from them. It came out great! I donated it to our annual toy drive.
If you look on their site they do sell plans for the Dulcimer.