I couldn't read your language on your website, so I didn't get very far on it, but I liked your blog pics. The pic you posted is the knife I was talking about, and it is almost identical to the Hudson bay knives. These knives usually had handles made of black buffalo horn or dark bone, with two or three large brass rivots holding the handle in place. My People and the other tribes called them the "Knives with Eyes," because of the large rivots.
As far as the sheath goes, go out on the internet and punch up "Beaded Knife Sheaths" and you should find many examples to help you decide on the type you want to make. If you don't know how to bead, there are websites that show you different beading techniques as well.
I have a few guns, but I collect mostly knives and swords, and I only buy them occasionally. I am an American Indian and a "Tribal Dancer" so during the warm months I travel often, to compete in different Powwows (Dance Competitions) around the US. If you are interested, go to my "Powwow Album" at my Profile section and there are photos posted there showing me and my People dancing for spectators to watch.