Wow, what a lot of interesting suggestions! I thought about using "whistlesmith" because I already use "buttonsmith" - I make ceramic buttons as well as whistles. (If you want to see my whistles, my website is www.hedgehogceramics.ca.)I liked "whistlewright" better, but was really hoping for a traditional word. Oh, well. But all of these are great suggestions! Who knows what else will turn up?
I thought there was a word for "bellmaker", too! Surprising to find there isn't.