Looking for a source for 3D foam of the kind commonly used on the back-facing bit of backpacks. Something like the Granite Gear Escape AC's foam, where the hills are maybe an inch or so apart.

If I can't find something better, I'll probably use a Z-Lite...

The blue foam camping pad at wal-mart is around $5.

What kind of pad is it? The only pad I've seen at my local Walmart is a plain, flat blue mat with none of the nubs I'm looking for.

This looks like what I've seen at Walmart:
http://www.walmart.com/ip/Stansport-Pack-Lite-Camping-Pad/9856753

But I'm looking for something with either hill and valleys or nubs/protrusions; something like this:
http://cache.backpackinglight.com/backpackinglight/user_uploads/1271739668_24119.jpg

The Z-Lite may be the only real option I have, but I thought I'd look for something better suited to my idea...

Aaron

What you are looking for is an egg crate style minicell foam. I know we use M200 for custom Kayak seets alot. But I can;t seem to find any eggcrate types.

However, you might want to look into this link:
http://www.suluk46.com/products%20%20-%20P4%20PF%20Sheet.html