You'll probably just have to get a roll of tissue. Most places (http://www.pacin.org/content.php?140-Resources) (look under matrials/tools/equipment) have unbuffered rolls of tissue in a width you need. I think I saw up to 65" somewhere, but it's expensive. Good thing is that you can use it for lots of stuff.

Unless you meant you were looking for mat board or something like that?

Jason