I think it would be a good idea to make harmonicas for all tunings with 11, 12, 13 and fourteen holes; more notes more fun.
I think you might be cery interested in the Lucky 13 diatonic harmonicas that the great harpist/innovator Brendan Power developed and sells. These harps have 13 holes and cover four octaves: the lower three holes are a bass octave similar to your usual holes 1, 2 and 3 in a ten hole harp. These are available in a variety of keys and various tunings. I have several of them and really have fun playing them. Check them out!
Check 'em out @noteguy:
Hey @Slim I’m jealous that you have some. I’m so excited to check these out!
My Lucky 13 models are some of the originally released versions. They are lots of fun, but I hear that the newest versions are much improved – I should have waited, I guess. On one model the reed response of one of the low octave notes was so bad that I went to work on it – and broke it !! My bad!
Some day I will look into buying new reed plates for it, but for now I can get by with the remaining Lucky 13 models that I have.