Yes I am well aware that the M model Kubotas come with 1 std rear remote.You know that they build some at the factory with the rear remotes right? It is an option, but some of them come already installed. Just like A/C's some are built without them. Whey you special order one, it isn't like they build it just for you, it is already built you just get to buy it. Even if my tractor came with rear remotes I would not have any thing to hook to them. So for me it would have just been an extra expense that I would not be using.
I don't know about tractors, but when you special order a car or truck, they build that vehicle for the person that ordered it. I know this first hand. They do not just take a unit from the line and put XYZ on it.