You're right, I overlooked Norton's waterstones, I was thinking oilstones only. Although they only offer them if four grit sizes, not really that different than their offering of three grit sizes in their man made oilstones.
I looked around a little more and the offerings of waterstones are as high as 14 different grit levels in the Shapton brand, that's a little extreme. What motivates the need for these products to exist? (https://www.sharpeningsupplies.com/S...s-P742C84.aspx)