Let us know how jacksterp's suggestion works out. BKC policies might prevent say a hole deployed 20cv blade from being purchased through the custom shop.
Try members Josh at razor edge knives; BigChris; Tom Krein Just searched on Tom and saw posts from 2016?
Certainly consider thinning blade stock out while these custom knife smiths have it.
Of course you can buy a custom grip as you requested in 20cv (or other steels), or use a Hogue Doug Ritter RSK MK1 G2 as the donor m390, to keep your Ritter Grip stock. I'd say it is a great time for this hobby!
As a wise old italian from the brickyard said "the question is not how fast do you want to go, it is how fast do you want to spend."