Be sure to post some pics of this stuff, Bill!
Also, I have some self-healing mats that I use for my model railroading hobby. Don't let the name fool you. They don't really "self-heal", they're just made of a spongy material so that when you cut into them, the gap closes itself. If you pick up the mat and bend it, the gap spreads apart again.
The advantage of these mats is that you don't have to worry so much about your blade wandering into an old cut in the mat and messing up the straight line you're trying to make in your new project.