I have a lot of cool knives that I don't carry because the factory sheaths were/are crap. Everyone raved about a particular brand of after market Kydex sheaths, I tried them and wasn't very impressed.
If you frequent a couple of the firearm related forums, you may see a gent going by the name "Unloved"
A while back he started posting pictures of some of his home grown Kydex gear and my interest got peaked. I finally sent him some of my favorite knives as well as some of the wife's items and am eagerly awaiting the new sheaths.
I've got sheaths coming for my SOG mini tsunamis, my wife's KABAR TDI (Small), and my CRKT ABC Operator. I was going to send in my large TDI, but the basement monster ate it.
Enough about what I'm getting, if you want to check out the gear, you can do so @ Invictus Kydex.
I should have my gear back some time next week and will be sure to review this topic sometime after getting acquainted with the products.