I can't think of anyone using a hammered dulcimer in a metal band offhand. Then again, I didn't know about Eluveitie and their hurdy-gurdy until recently, either.
Me, I consider myself slightly spoiled. I've been lucky enough to see Dead Can Dance twice, with Lisa Gerrard on the hammer-dulcimer (and other things), and you just can't get much better than that. AND, they have a hurdy-gurdy, too.