The nearest sounds to a concertina that I can get on my PC are listed in Sibelius as programs 20 to 23. 20 reed organ, 21 accordion, 22 harmonica and 23 tango accordion. There's not a great deal of difference between them and they're not a million miles away from a concertina sound. The Idea of a midi concertina is fascinating. Would it work for an anglo? I had toyed with the idea of re building a cheap keyboard into a kind of electric concertina trainer.