The Case is made from 4mm plywood and milled on my Shapeoko 2.
To design the case, I used Cadsoft EAGLE. I have only seen very few people use it for that purpose, although it is quite nice to use (at least if you're already used to the workflow) and the size restrictions only apply to components, not to drawings.
The design is pretty straightforward: a box with finger joints and a separator for the battery compartment.
The most exciting part is the battery cover: it slides in and out without using anything but the plywood and no extra parts.
The design files can also be found in the GitHub repo.
For CAM, I chose the best tool that I had: me. I traced out the toolpath in eagle with a line width of two millimeters which is also the size of the bit I used for routing. Then I used a program that I made for this very purpose (might get released on GitHub soon) to convert the line path directly to GCode.
Since this is almost as close to G-Code as writing it by hand, the generated toolpath is very efficient.