There are a number of scams out there on farm equipment, utility vehicle, farm equipment, etc listings.
Not sure how these people operate, they use hijacked ebay accounts and reroute your $$ during the transaction, but it is getting easiser to spot the scams.

If you see a listing of interest in these categories, look at the seller information, other listings, listings from feedback.  If you see:

All their other listings are completely unrelated to the category,
The Listing Category doesn't make sense (ie, antique jewlery is the category / Kubota tractor is the listing),
Feedback where they are ALWAYS the buyer / NEVER the seller
Feedback on items where they are the seller in unrelated listings (ie, computer harddrives and components are all their previous sales)

Then chances are the listing is fake.

Good Luck, and be careful!