I only just found this post, but I've been saving tp rolls for a few weeks, and think I have found the sturdiest and thickest rolls ever. They came from a pack of tp from Walgreen's. It was the ology brand that is made of bamboo. The paper is just okay but the rolls are really good. I don't know if all of them are like that or only the pack I got, but if you want a good stamp that wouldn't crush or deform, it might be worth buying a pack of these to try. You can even use the paper for making handmade paper; the bamboo content should provide an interesting texture to your paper.
I can just see all you craftsy people making a run on Walgreen's, lol!
So I'll have to try this project now....I saved the rolls just knowing I would find something to do with them! This is really pretty, and I love linen and bright colors together too.