Hi, I'm 14 and I made this using Google (Trimble) Sketchup. I haven't tested this yet, and haven't added some way of securing the two pieces together yet (clips maybe). The bottom caves out a little to make the model look like it's floating in the air. Renders were done in Blender using Cycles render engine.
Props to http://solidworksbootcamp.com/raspberry-pi-board-b-enclosure/ for the inspiration!