I just wanted to make a post about three sheath-makers who post here. I use their products, all of which are excellent in my experience. Their customer service is excellent also.
Mashed Cat - interesting and very cool trademark opening at the bottom. Excellent fit, retention, and finish.
http://mashedcat.com/Buy Brown Holsters - the Waki sheaths are excellent. Excellent fit, retention, and finish. The open spine idea is great. I assume it was his idea first because I saw and read of his first, but I've seen simlar ones from others since.
http://buybrownholsters.com/Rainwalker - The kydex X-Loop is great as is the SKDL. He's made things other than knife sheaths for me which has caused me to carry certain tools more often, more conveniently, and more comfortably. Excellent fit, retention, and finish.
http://rainwalker15.googlepages.com/index.html-----------------------------------------------------
Everything I've bought from these three have been excellent. If you haven't tried kydex but are thinking about it, I recommend these three for a quality product.