After hearing Popper effortlessly bend the 10 hole on his E harp on several occasions, I figured I would get it on my C harp with a little more practice. This didn't happen.
I thought I'd work my way up from my G harp, on which the 10 hole slides down easily. I never made it past A to B-flat.
Who else uses the 10 hole bend? Magic Dick's Whammer Jammer and Big Walter's Trouble in Mind come to mind, though these are both on A harps.