Don't know how well this would work even if you were to fabricate custom scales. The ss liners in the frn handles are nested and smaller in size than the ss liners on the G10 version. Why not just pick up the G10 version as well?
As mentioned, we did make Endura's and Delica's with G-10 scales. They also had full liners. The FRN models have nested liners and creating G-10 scales for them would be quite difficult.