Klara

https://y-knotlace.com/natural-lace Ignore the pictures. Pick your colour and then select the width you want.

There is also Deco-Cuir in France.

You can put a piece of leather over the parts where the thread catches to deflect it (guess how I know). Huge jaws are definitely not necessary (unless you are working huge pieces) but looking at your design I wonder how far the jaws actually open? You may not always sew two flat pieces together. But the great thing about having made it yourself is that you can change it, or build another one, if you think of improvements.

The collar is beautiful, but what really impresses me is the hardware! I wouldn't dream of making a buckle. Kudos to you!

Just for education: For the reasons mentioned above, horsehide was still used for orthopedic prostheses some 20 years ago (couldn't say for now, then it was a patch...)

I don't like Velcro as only fastener because I find it separates too easily. That said, my cheap snaps from Aliexpress aren't secure either. Would buckles be an option?

What is your hypothetical bedspread supposed to do? Just make the bed look good? Then I would leave the hide whole in its natural shape (possibly cutting off frayed bits at the edges) and just put it on top (like those cowhide fur "rugs" you can buy at IKEA). Protect your bed sheets from your dog? Forget it, use a washable fleece blanket (just got a sniff of mine - fortunately polyester dries fast). Protect the (guest bed) from dust (that's what my woven bedspreads do)? Then you'll need to create a rectangle the size of the bed and preferably add strips on the sides that cover the mattress. I don't think leather will drape well, so I wouldn't make the spread much loger that the bed (no corners). For getting the shape you could go patchwork all the way, or put your biggest hide in the middle (with straightened edges, unless you feel like assembling a puzzle), or... You could assemble the parts by sewing or lacing. (I had to cover beds 90 x 190 cm and I only have a 100 cm loom - allowing me to weave 90 cm wide. So I wove 90 cm wide for the top and added two strips for the sides, figuring that would look better than having a seam in the middle of the bed.) I don't see any need for a lining, nor for "finishing" the edges (beyond cutting off anything you don't like the look of).

It's probably too late by now, but another way would have been to buy a pricking wheel as mentioned by toxo and work with an awl (as described by Al Stohlman). There's a steep learning curve, but once mastered it is probably the fastest and most versatile method.

Now that I see the picture I remember that I have a tool belt/bag that looks similar. It must be split leather (I bought it before getting into leather work and never thought about the material) and is holding up well. In your place I'd make a simple bag, dye it if desired (not sure stamping would work) and then seal it with Mop n Glow (the more water resistant, the better, for an outdoors bag). And then just use it. Either it holds up, or it doesn't.

Then what do they do to create classic "split leather", the plastic-coated one? Is it really the plastic coating that creates strength? For I have a belt (bought extremely cheaply for its beautiful buckle) and stuff (belt, dog collars, leash, bags) I've made out of a split hide which I bought by error, and everything is holding up perfectly. So I wouldn't say the stuff is useless - but I wouldn't know how to use it either...

Single hole punches are great for individual, big(gish) holes, but I wouldn't want to line up the holes for a seam with them. One of the major advantages of the above linked tool is that it gives you the same distance between holes. And if you go two or three holes back with the 6-hole tool (making only 3 or 4 new holes), you greatly increase your chance for a straight line. The 2-hole tool is for curved stitch lines, but you'll still have the same distance between holes. Looks like a useful set to me!

As far as I know, Damascus is the better choice for swords, where you have a long narrow blade that needs elasticity. For kitchen knives it's unnecessary, and for a round or head knife even more so. So you'd be paying extra just for looks...

Vergez Blanchard still make them, and Deco Cuir is selling other brands for less money: https://www.decocuir.com/collections/couteau-a-pied-cornette (I believe there is an English version of the site, but living in France I can't find it). The cheaper ones on top can also be found as putty knifes in glazers' supply stores.

If you watch the above mentioned video by Saddleback Leather you'll see why that is not a good idea:

If "not perfect" meant that the colour was wrong, I'd be unhappy. If a pug breeder tried to breed pugs with longer noses and killed the puppies with the shortest noses, I'd accept that. If a puppy had a misshapen leg or mouth, I'd applaud the breeder for euthanizing it (and I am NOT happy when breeders have a puppy with mouth deformities operated on and bottle feed it. As you said, in the wild it would die and that's how it should be. With the difference that in the wild it would slowly starve to death whereas a breeder hopefully puts the pup down quickly.) First and foremost a dog needs to be functional, healthy and able to enjoy live. Incidentally, I don't agree with the people who keep alive their old dogs with dementia, incontinence and unable to stand up alone - I wouldn't want to exist like this and I won't do it to my dog.