Joe Hunt sold Joe Hunt Magnetos some years ago. I think an Australian guy owns it now....and that's all I know about that.
Joe Hunt, Cirello, Vertex, Frankenstein, Schaefer, etc, ALL these mags were sourced from a manufacturer in Sweden (started out as the same mag). Each American company would purchase direct and then modify them to their specs, slap their label on it and then sell it as their own specially prepared magneto. The brand name often helped the racer know how the mag was set up (output rating, etc) although this changed over the years. (Joe Cirello also manufacturer his very own mag, 100% in-house, although very few are in existence.)
We use Don Zig for our mag service. Tom Cirello is another good option. Lastly, there's a guy we use up here who is an FAA certified magneto rebuilder (mags originated from aircraft) and he is one of the most detail-oriented technical geeks I have met...meaning I have faith in his workmanship. If you want to go this route PM me, but Cirello and Zig can take care of you.
LO