My Crabb 40 key C/G has 8 fold bellows. Somewhere, I have correspondence between the original owner and the late Neville Crabb regarding the wisdom of fitting 8 fold bellows. The customer was quite adament that it was what he wanted, despite Neville's protestations, and he eventually agreed to make them. And very nice they are too...and certainly work well for my style of playing, though I can see that they would probably lack a bit of control for fast ITM.
I'll try and dig out the correspondence as I can't recall just what Neville's objections were based on.
Edited by malcolm clapp, 24 October 2015 - 05:37 AM.