A Raspberry Pi case design you can use to cut out a case for your pi out of paper, cardstock or plastic sheets. (http://www.altj.com/raspberry-pi-case-made-from-cardboard-cardstock-paper-or-plastic/)
This file can be used directly by a Silhouette Cameo to cut out a case for your Raspberry Pi.
The case requires no glue for assembly.
I've made cases out of plastic sheets (overhead slides) and cardstock. The plastic sheets look cool but are more difficult to fold/assemble.