Here's a broad and varied collection of videos on YouTube that feature players of the hammered dulcimer around the world (but not America --- that's a different playlist).
I started out with the region where it is said that the dulcimer originated --- Iran and India --- and started touring east from there; but after a while I just randomly listed a hodgepodge of locations. Maybe someday I'll organize them further, but hopefully this visit to many places will be of interest for browsing!
www.timothyseaman.com/