The closest you're going to get are some models of JD that are made in Waterloo. JD still makes their own engines for the big stuff. I'm sure they get some components from overseas, it's simply not economical to make a $2 plug when you can buy fifty from china for the same price.
As far as the small tractor market...no. Even if JD wanted to, putting that kind of R&D and setup money into a small tractor line when the Yanmar stuff is perfectly fine would make no sense from a business prospective. Being on TBN gives a bit of a skewed perspective on the US market. We tend to think 60hp is a big machine. Any decent sized farm in the US is going to have at least a 100-150ish HP machine in the stable, if not multiple larger units. That's where the money is in tractors, and that's where companies like JD, Case/New Holland, and even Kubota are going to put their focus.
The startup cost of trying to create a new US only brand would be enormous. You'd have to find a domestic source of engines. You'd have to find/make rears and transmissions. You'd have to make the sheet-metal, the driveline, the computer system, the DPF package(I think it took Mahindra 30 million US to engineer around needing one). Find a domestic source for fuel senders and hydraulic pumps, the list goes on and on.
At a wild guess you'd need at least 5 years and a couple billion dollars to even get off the ground. Maybe more, if you ended up needing a foundry to make castings.
die: