They sell this stuff across the street from my house. I actually just bought one less then a week ago and cut it up to use as sit pads around camp (you can see it in the Utopia thread).
The link is super long, so if it doesn't work, just search the subject line at www.mec.ca. I think it was 15 bucks or so...and they have a number of different thicknesses and lengths. Just like the GG stuff, it seems to insulate amazingly well for its thickness.