Well I was kind of thinking about buying and cutting up one of those ubiquitous blue foam sleeping pads. I think they're about $6 at walmart, 3/4" thick, waterproof and pretty tough. They come pretty big, so you should be able to cut and layer them to make it thicker if you want, hell you could probably make 2 or 3 seat pads with just one of them. Just thought I'd mention it. I want to make a nice aluminum (polished or painted black? ....hmmmm) cafe seat for my new $25 "Ikea" CB550K once it's running and i was planning on using the blue foam pad.