MRC Interesting. Didn't expect that. My hands are big enough for a standard keyboard, octaves are easy, ninths well doable, but I struggle a lot with tens. I am curious how a 6" keyboard feels. I think a 5.5" could be too narrow because of my sausage shaped fingers; even now I feel somtimes to get stuck between 2 black keys when I play the whites near the fallboard.
Would be nice if a 5.5 and 6 inch standard etablishes and most important: The big companies would start to make bread and butter products with those narrower keyboards. Actually, this makes totally sense, because this way they can lure kids into their brand, offering a $1000 digital that is cheap enough for parents to try out but doesn't feel like a toy. Basically make narrow variants of their best seller lines.