Folks, you can build this for $3-4K. The
PhlatPrinter 3 is about $1,850 (shipped) and the foam I used cost me about $1,250 or so. Glue was a bit over $100 (so far). I had to buy support rollers, side rails, and I already owned a shop vacuum. My shelter cost about $250.
I can provide you with the SketchUp model (for CarBEN and/or Dave Cloud's Dolphin) and I have the CAD drawing and all the g-code files for CarBEN. I am doing this with the principles of open source design - we all learn as we go, and help improve the process as we go.