DIY Blanks- Pink Panther Project

I have been a big fan of http://www.korduroy.tv/ and have been very interested in various shapes and board materials used by those trying to surf/save $/ make something unique. Recently, I have begun shaping my own blank out of rigid foam insulation boards that you can buy from Home Depot. The material is actually extruded polystyrene (XPS) and feels like it SHOULD work. So far, I have set the rocker size and glued 2 1.5inch sheets together to create a stringerless simmons/ soapbar shape that I have wanted to make. If the blank works out, I plan on using bamboo glassing from GReenlight surf supply and making my own fins. If this works out, I am going to grab a electric planer and 1000 sheets of sandpaper .... I should have a board that I shaped for under 100$.

Has anyone tried to make their own blank before?