You could always come to the Scandinavian Squeeze In in a couple of weeks time nedar Lund in Southern Sweden. You'll hear plenty of polskas on concertina there. Go here and click on SSI on the left hand menu. I'm told there are still a couple of places going. We've been the last 4 years and wouldn't miss it for worlds. The web site also has quite a bit of information about concertinas - if you can read Swedish!

Chris