Greetings!
I got a custom 'ray skin sheath for my La Griffe from Chris Kravitt at Treestump Leather. Its beautiful. I chose the black ray skin and he gave me the piece that had the little pearly spots down the middle. He also works with leather (obviously) and a variety of other exotic skins (other than ray skin that is). He created an excellent piece, I'm very pleased. Next on my list is a sheath to carry on my belt for the La Griffe. I find the neck sheath too bulky for me personally; I'm rather petit and slender.
We're going to the NCCA show in CT tomorrow and are looking forward to seeing Chris, actually. He'll be in Atlanta this year too. He has a website at treestumpleather.com, or some such thing, but it doesn't really do his work justice. Chris is an excellent craftsman with a real talent for tooling.
Tell him I sent you. Good luck!