Lori Ann,
Yes, the picture you linked looks like polyboard (aka StarBoard). I found a supplier in downtown Seattle, where they have 4X8 sheets of the stuff. There are many different types of grades and thickness for different purposes. The grade that I wanted could only be purchased as a 4 X 8 sheet, at the low low price of $360. So I opted to purchase a smaller quantity from West Marine. Looking back I think I should have purchased the full sheet. I've been using the stuff as backing, as a tray, as a mounting platform for my crab pot pulley, etc...
Many cutting boards are also made from polyboard, and I've even taken one of the wifes cutting boards when I got into a pinch and was alittle short on the material. I told her that it broke :roll:
I'll get the name of the supplier if your intrested, I have a business card somewhere