It is quite smart to use the word of mouth. Actually I am considering and already contacted the TBN to talk about the possibility of launching an advertising program. But there is still a lot work to do before that. Your ideal might make sense. Maybe we can work this out privately.
If the price is right there will always be a buyer. What will make or break you is those first few customers. If everything works out well for them and they let people know then it'll go far towards continued new sales. Also it would be wise to sponsor a forum like this and maintain a constant presence. If there's any problems make sure you are upfront about them and what you're doing to resolve the problem as well as what you're doing to make sure it's not going to happen again. If possible I would even offer a few tractors to members on the forum to try for a year free (or at a really reduced rate) as long as they post at least once a week about how well it's going (pros and cons).