So, roughly 1600 to 1763?
I would agree that neck knives are over-represented these days. As noted by several people above, there isn't much evidence that they were used by white hunters. However, a lot of people now seem to want them. I saw a picture of an Indian with a neck knife when I was about 12 years old and thought it was cool. I cobbled together a neck sheath for an old knife I had. I very quickly abandoned the idea after wearing it for a while... always swinging and flopping around, and not as easy to access as you might think. I got neck knives out of my system a long time ago.
I would strongly recommend that you read Joseph Doddridge's
Notes on the Settlement and Indian Wars of the Western Parts of Virginia and Pennsylvania from 1763 to 1783, Inclusive. It is available to read online for free right
here. Doddridge mentions the hunters carrying "scalping knives" frequently, and he also described them carrying clasp knives. He specifically stated the scalping knife was carried on the belt. He didn't really give any detail as to what they looked like, but trade knives of the type associated with scalping knives did not change much over more than two centuries. This 1628 image by Matthaeus Merian (1593-1650) shows John Guy in his first encounter with Beothuk Indians in what is now Newfoundland in 1612:
View attachment 236476
It was a peaceful encounter. Note the knives the Englishmen are offering in trade, and compare them to this "scalping knife" from Dean Oliver, of River Traders:
View attachment 236477
The knife John Guy is holding (in the foreground) does appear to have a ball-end grip, but there was some variation in handle design.
The upshot is that I would agree with the folks who recommended a scalping knife for you. I don't know enough about clasp knives of that period to discuss them, but will look forward to reading what more knowledgeable folks contribute.
If you want something a little different, and considerably larger, you might consider a plug bayonet:
View attachment 236478
That one is a reproduction, but it is very similar to one taken from an Indian during King Phillip's War (1675-1676). The original, which is believed to be of French origin, is described and pictured on the
Deerfield Raid website. I think these are typically 18"-20" long. They are intended to be stuck or "plugged" into the muzzle of one's musket for close-quarter combat. Obviously, the musket is unshootable while the bayonet is in place. I suspect they were more frequently used as big knives, but I haven't really dug into the history of their use. The Rifle Shoppe sells parts sets in several variations for people who would like to assemble one, and they tell us that "
...Erik Goldstein states that the first mention of [French]
plug bayonets in Canada was in 1647. In 1689 many of the Indians had them."
So, you have options for authentic cutlery, but you might have an easier job if your timeframe could be narrowed somewhat. Research is so much easier than it was even a few years ago with so much of the source material, like Doddridge, available online for free.
Best regards,
Notchy Bob