I'll have to say, I'm with RAT here. I have not had a knife poke through a leather sheath.
I have heard of traditional Scandinavian sheaths made with a leather-covered wooden core, but they look funny and kind of unattractive to me. Also, I have seen photographs of Saami sheaths made of reindeer antler, with a leather "throat" added on at the top. Some of these are very nicely engraved.
I don't know about the construction of eastern Indian sheaths, but I have seen a number of plains Indian sheaths in museums. The beaded ones are typically made of parfleche (heavy rawhide) covered with buckskin. The beading is done on the buckskin cover. There are also a number of plains Indian sheaths just made of parfleche, and often nicely painted. I have worked with parfleche, and made a couple of sheaths from it. Here is one that was copied from one I saw online, with a red trade cloth binding. Don't pay any attention to the
biscochitos... They are long gone. I still have the knife and sheath, though:
Parfleche, the real thing, is as tough as Kydex, and you can wet mold it to hold a knife firmly in position. I use tin snips to cut it when I'm working with it.
I have made some sheaths of vegetable tanned leather with thin (deer) rawhide covers. These are fun to make, and they are very practical, giving good protection to the knife and the person carrying it. I think they have a very appealing, rustic appearance. This is a knife and rawhide-covered leather sheath I made for a buddy a while back:
I use 6-7 ounce leather for the core, with a leather welt, and I wet-mold the leather core to the knife before covering it with rawhide. Some people use heavier leather for the core, but I don't think it's necessary, especially with the rawhide cover. I soak the rawhide in black tea instead of water, to give it a little color. The actual sheath is not orange, as shown in the photo. That's just the way it came out on the iPhone camera. Unfortunately, these are not authentic to any time or place on the American frontier.
I think concerns about the knife poking through the sheath may be realistic with regard to "neck knives." For the life of me, I cannot understand their popularity. To each his own, and I know they were used to some extent by eastern Indians, but I just can't tolerate having something like that flopping around on my chest. And, if you are running from an angry bear or something, and you trip on a log while going full speed, I could see the knife jamming against the ground and poking through the sheath and beyond. The bear might get a free lunch.
Best regards,
Notchy bob