Lots of tractors and accessories, much of it in G and larger but a goodly amount in O scale at Southern States, a Garden supply store in Manassas VA. I don’t know where it is elsewhere offered.
Pretty stuff for a farm layout (which mine isn’t)
Dave, you can always try www.diecastdirect.com and search for farm and 1/43 and 1/50
Tractor Supply Co. is also carrying the John Deere die-cast models.
http://www.mytscstore.com/default.asp
I wish Cat and Deere die cast suppliers would offer some models of their vintage equipment. My layout is steam era and all the good models they offer are modern.
Regards,
Roy