Navajas, Nontrons and Laguioles all date back to the 18th century. Nice productions repros can be had (if you want to call them repros, they're all very old designs). But I haven't found anything resembling the Valley Forge knife that wasn't cheap junk. And stay away from the $10-15 navajas. I got one for a pirate costume and that's about all it's good for. I think it's joker that makes a horn handled ring-locker that greatly resembles the common clasp knife of the colonies. Maybe a Svord Peasant would be close enough? I'd love to know what you find, I'm always looking to find new kit for the pirate/ren events.
Frank