I love the sound of the chemnitzer concertina. One day when I have some extra scratch (think small lotto win), I’d like to find me one of these babies and learn it. I think that since I have some experience on the triple row accordion, which is also a bi-sonoric diatonic instrument I’d be able to pick up the fingering and learn to play it with some effort. There are usually some beauties offered for sale at concertinamusic.com.
27th Street 
Beautiful. It looks complicated to play though, but sounds like it’d be worth it to learn.
gee, I see what you mean by the small lottery. but they are lovely looking…