Hum, good question. We bought some regular black pipe foam from a local heating and air company. However I still haven't used it. There is some places on the net that sells colored foam . I will have to search to find it.
I have bought stuff from Tellico 4x4 before good service and prices. I bought some padding a long time ago for my Jeep and the shipping was more than the padding so I like to pick that up local if I can find it. I'll check out the links and thanks.
Some of the padding I see for sale seems pretty expensive. I've always wondered (but haven't actually tried it) is the "worms" or whatever they're called that the kids use for swimming. Some of it has a hollow center, it's available in lots of colors, would it work?