Hi Weaver,
I don't have a specific fleece section, though I can try to make one as I update my photo albums. I am reworking where I host my pictures, so hopefully soon. Let me see what I can get together for you. Do you have any colors you like more than others? I can get together some stuff for you to look at.
Otherwise, almost all of my fabric is snuggle flannel, so usually, the cubes and pyramids are pretty cushy regardless. I can also add extra padding to the floor. Also, fleece on fleece does not cost extra except in liners. The extra padding is $1 extra.
As for the size, a M is usually a pretty good choice for a martins. A large would be pushing it, it would probably end up a little slouched. The medium is a very good size pyramid though. It fits about 4 rats.