Hi Sam!
I found a Nyckelharpa buider in Falun, Peder Källman .
Unfortunarely his site is in Swedish only but you can send a mail to him and we can hope that he understands English.. He seems to be in the right age for that! Or... perhaps I could try to translate the text on his site for you.
I've been to the Falun Festival once but now my MS is too bad so I can't walk a lot. It would have been great to see some Mudcatters!
Berit