Gemeinhardt holds a patent on what they call a "dual use trombone":
https://patents.google.com/patent/US7608767B1/en
It's basically a symphony-bore tenor with interchangeable leadpipes, one of which is extra long with a small shank receiver. It's supposed to function like a dual-bore trombone. The patent lists Richard G. Barth as the inventor. Googling Mr. Barth, I find this entry in the
FAQ for Big Mouth Brass:
Q: Who is BMB?
A: Big Mouth Brass is a tuba company initially founded as part of the W. Nirschl brass division of the Gemeinhardt flute company in 2006. Models J-844, 845 and 744 were, and still are, built on German tooling purchased from Walter Nirschl. The other models in the line were designed and developed by Richard Barth. When new ownership at Gemeinhardt decided to focus solely on woodwinds, Mr. Barth decided the tuba division was too important to let fade and so BMB was born in 2010.
Piecing things together, it looks like the new Gemeinhardt instruments might be the same as the old W. Nirschl stuff.
The W. Nirschl instruments were "globally sourced" (China, Brazil, India). Gemienhardt's own site mentions the US, Taiwan, and China. Take you pick. Given the pricing on the Brook Mays site, I'm guessing China - but there's a lot of factories in China, and which one makes which instruments is usually a pretty well guarded secret.
I know someone with one of the Dual-Use Nirschl trombones. I don't recall him using the conversion pipe much, but he was reasonably satisfied with its performance as a symphonic tenor.
