I had a table top that was veneered with small pieces of Osage Orange. It had a beautiful color as it aged. I've wondered too about using it as a grip, too.
It is also known as Bois d'arc, loosely translated as wooden bow, or wood of the bow, mock orange, hedge/horse apple ( I think). It was/is the premier wood for making native-american style flat bows.
It is also used for fence posts, as it is rot resistant. I've heard that you have to drive nails in it when it is "green", as it gets so tough and hard as it ages/dries. How did you work the knife grips?