Jim,
Here's what I know. One year ago (June) Mondovi wineries tested four prototype Yanmar tractors in their vineyards. They were so impressed that they expressed an interest to place an order for the production model T80.
The T80 is a rubber tracked vehicle and equipped with a new steering that has been compared to a BMW seven series car. And the units are said to be reasonably priced with tractors offering less features and horse power.
Rainbow Agriculture and Yanmar of Osaka Japan have struck a deal to import and service Napa, Mendacino, Lake and other counties wine vineyards.
I had pictures of the prototypes, but lost them in a hard drive crash....I am pretty sure (by now) that they are here in limited numbers, and probably testing the market.
Regards, Mark
****edit**** I just did a google search on Yanmar T80 and found some older articles (November??)...but no pictures.