The cut nail is still being manufactured, more as on oddity I suppose. We've discussed Tremont Nail (longtime manufacturer in Massachusetts) here on the forum before. And cut "flooring nails" are readily available here in the US in most lumber centers, but they're not mainstream. I can only speak for this side of the Atlantic.

Tremont states it makes "steel cut nails for restoration projects and remodeling." I think Northern Hewer is seeking when the practice of using cut nails became secondary to wire nails (common nails).

NH, I think you still have questions remaining about time periods, usage of one nail type over the other, correct?
Nice comment by the way: "you're never too old to learn."

And I would think Chris How's paper would fit nicely in an issue of Timber Framing. Not your run of the mill feature.

Don Perkins
Member, TFG

to know the trees...