I really have not seen many large builds. As far as I know I get asked once a week about it but no one has actually built one. I am pretty happy with a smaller build. I can see some people wanting to cut full sheets 4’x8′, but really that is only a few people not the majority. With some mid spans support I still think it could cut full sheets as is of wood.
So larger rails is just a larger footprint for us people who want smaller machines. Best of both worlds?