Hello, jmaendel. There is a popular site about dulcimers called

everythingdulcimer.com

On that site is a series about building a hammered dulie:

http://www.everythingdulcimer.com/index.php?option=com_content&view=article&id=119:part-i-of-ardies-hammered-dulcimer-building-guide-introduction&catid=14:everything-dulcimer-articles&Itemid=113

I hope it's helpful.