There's a long European tradition of half round/round/head knife/lunette knives, call them what you will, for leather working. most have a single upright central handle like the top one in post 17, a few have it leaning to one side. There's about 8 pages on using and sharpening them in Al Stohlmans "Leather craft Tools".. Unfortunately the only round knives I could find (I'm not set up for heat treating even if I had time to make one ) were prohibitively expensive.
https://hwebber.co.uk/shop/c-s-osbo...g-stones-leather-knives/saddlers-round-knife/
They are less straight from the US but then you could get hit for import duty. I've been looking for a old Barnsley made one to do up but so far nothing worth working on has turned up.
In the end I went for a Grohmanns Ulu, made a leather sheath for it and on RVs suggestion a indented chopping board from elm, since I finally had some. Theres a thread somewhere.
It cut through the what? 5 MM? veg tan I was working on as sweet as a nut. Then I ran out of leather!
Evidently there's a almost unheard of womens martial art/defence based on the ulu, . Not my thing, just stumbled on it when looking to buy a ulu.
ATB
Tom