I thought this was made of polymer clay until you showed the raw meat! Holy crap, girl! Easily the niftiest thing I've seen on Craftster. YOU SHOULD WIN!
For the roll up case, I'd assume a ribbon would work the best. If you had a snap or button or something, it might end up not rolling as tight if you had less pens in it.
Heyhey~! I'm definitely joining this craftalong. Nothing much to show yet, just a pencil pouch, but I'll have more later today. I just figured out how to do binder covers, mwahaha!