Here are some examples:
https://vzgrips.com/shop/revolvers/
But it's really expensive to design up a lot of variations, and if the person doing it doesn't share your thinking about designs, you're kind of out of luck. And it doesn't really address the "one size fits some" issue very well.
My understanding is that's how the old school guys like Hogue, Pachmayr, Farrant, Herrett, etc., got started: Custom grips on an individual basis.
CNC also has the challenge of unit to unit variation in frames. S&Ws aren't perfect, but Rugers are so different that Herrett won't even take a job on a GP100 unless you ship them the gun to fit it. Which adds a heck of a lot to the cost. Last I checked, it was ~$200 for the stocks, $100 for custom fit to the frame, and two-way shipping of the gun.
There's a guy in Houston making a few dozen variations of grip frames for Ruger single actions on his CNC, but they start at ~$350 each. The actual mate up to the contacted surfaces and fastener positions of the Ruger frames is very consistent, but the widths are highly variable, requiring each grip frame to be hand-fitted to the frame it's going to be paired with.
There's a guy in Michigan 3D printing handgun grips. I sent him my modified GP100 Hogue and got back an abortion. Fortunately, he was good about refunding what I'd paid him, so I only lost my time and outbound freight.
I guess something I would like to see, which might be the sweet spot of balance for CNC and hand made custom, would be CNC'ed blanks with all the inletting done, so the DIY guy could whittle as he wanted, but the precision work that isn't particularly interesting when you're trying to make the outside of it exactly what you want would be done well and efficiently for you. Rugers would have to be rough inlet, but that would still be a real benefit to have the internal cavities 95% complete, flat, uniform depth, screw hole piloted, etc.