Sorry to hear you will not be building it... Yeah foam ain't cheap, I bought a total of 8 sheets of 1 1/2" to build my current project, at $22 a piece... I reclaimed some of the materials, and lots of contracting job leftovers but if I had to build from scratch I bet I would have spent $1,000+. I like your design and if somebody had a bank roll to spend on it, it would be one bad a$$ shack!