Great Idea! Inflatable Concrete Structures

I just learned about Concrete Canvas Structures, a small business that formed from the great idea of instant emergency structures, inflated and hardened into hardy, sound shelters. They can be bermmed for insulation and protection. And they are water-proof. What intrigued me most was the minimal time involved and permanence of the structure. There are lots of other uses for this. I also wonder what the size limits might be?