The CA did come in the three configurations Bruce mentioned. The single front wheel seems to be the hardest to find. However, that will depend on the area of the country you are in. I've been told that vegetable farms used a lot of the single front wheel tractors. It seems to me that the single fronts are the lowest quantity still around for all of the makes. Get the CA, it's a great little tractor! I don't think the CA's are rare, but a SFW version might be unique at a show. I've also been told that they steer easier than the "regular" tricycle tractors.