If this isn't a common thing, how about a backpacking air mattress? Something like this will roll up as small as a waterbottle but is very comfy to sleep on if you have a flat surface. It's inflate/deflate vs. rolling it out but it's way smaller than any foam.

https://www.amazon.com/Klymit-Static-Lightweight-Sleeping-Navy/dp/B085D7WXT2