I talked to him last year. He's a good guy that fell on hard times when he lost his job. While looking for work, he built one and sold it which led to another and so on. They are a bit smaller than they look but they appear to be very well made. His basic one doesn't come with a floor but he can add one.
He builds them in a warehouse in the industrial park near Brother Industries in Bartlet.
I'm not affiliated with him in any way. I admire his courage to branch out after loosing his job. I was out of work for nearly a year and can appreciate his predicament.