Patrick Grashorn of this forum (aka "Executioner") does a lot of fine work in custom grips but works mostly in Elk horn. Considering the prices of custom work with hard to get real Sambar Stag and the fact that it's a mixed bag and hard to find matching sets with nice bark, you may want to check him out.
HERE'S one of his threads with examples of his work in the "accessories for sale" forum.