I'm crazy about concertina music right now, even toy concertinas, so here's my favorite version:
"but we'll meet again by the roses, in the valley of the moon"
I'm rediscovering some "Dutchman-style" polka bands, from Wisconsin or Minnesota: Brian's MVD, Karl's Country Dutchmen, and some of earlier bands like Elmer Scheid or Whoopee John. All use the chemnitzer concertina in a small ensemble. Arrangements sound structured but there's never anyone reading music.
Mariechen Waltz was the theme song for Whoopee John Wilfahrt, the first of the midwestern polka bands to record.