Busse makes great knives but sidesteps the issue by not supplying a sheath at all. Personally I find it annoying that a knife costing several hundred bucks ships in a cardboard blade cover, but probably anyone spending that is either going to keep it pristine (ie collector) or commission a custom sheath.

I like Kydex myself. A mixture of Kydex and nylon is really useful. One thin I often do with Mora knives is to stick the cheap but effective plastic sheaths they come with down into a leather holster. You get the beauty and character of a handmade sheath with protection of the plastic one. I will try to take some pics after work.