Have you guys discussed some of the pre-molded shapes available for home renovation work? They are mostly crown moldings, decorative ceiling elements and the like. I'm sure that in the hands of those here they'd find all sorts of new creative lives.
Also have you discussed using extruded polystyrene insulation, the blue or pink insulating board you find at building supply stores. It's usually readily available in 1, 2, 3 and 4" thickness' and is much stronger than Styrofoam.
