Drm7, in asking "No tractor guys here?", you called my bluff.
I strongly recommend that you consider a grey-market Mitsubishi or Satoh tractor if you're looking at Japanese equipment. They are quite rugged. Parts and support seem to be better than for many other "greys". For examples, getting parts for grey-market Kubotas and Hinomotos will be a major problem, as Kubota got an injunction to stop importation of greys under its name to the US, and the parent company that made Hinomotos (Toyosha) went out of business over 10 years ago.
Two parts dealers in particular reply frequently to requests for parts and troubleshooting on the busy Yahoo! forum for Mitsu and Satoh tractors:
http://groups.yahoo.com/group/mitsubi****ractors
One of the dealers is in Virginia in Roanoke, and a fine fellow he is.
I also compiled a general information and vendor list on these tractors that is available under "Files" in that group. You have to join and sign in first to access the file.
My opinion is that a newer Japanese diesel tractor is generally a better choice for most people in your situation than a 50+ year old American tractor. The Ford N series has a devoted following with plenty of support, but other older American tractors can present problems in that area (I speak as having had experience with an orphan Minneapolis-Moline model BF that
nothing was available for). Keep in mind the age of these units and the disadvantages of gasoline-powered tractors, and the superiority of a '70s-'80s diesel becomes clear. You can work all day on a lot less fuel, you don't have carburetors, etc. Also, these days you'll pay as much for a decent Ford N as you would for a Japanese grey-market diesel.
Oh, by the way, diesel Mitsu tractors generally use 15W40 oil rated for diesel use just as you would expect, with a recommended change interval of 50 hours. On our circa 1980 Mitsu D2000 II with over 1400 hours, I change oil using Shell Rotella about twice as often since it takes me over a year to put 50 hours on it. I figured you BITOGers needed to know.
We look forward to seeing what you decide.