After some research I worked out the features I felt I needed.
1) Enough room for my starter turning set.
2) A couple shelves for checks etc.
3) Some drawers for bits and pieces.
4) A door. (To keep the woodworking dust out.)
The dimensions came during the design process. The tools had to be spread out enough to get your fingers around them and I wanted at least one spare spot. This meant a width of 20". I figured a 1.5 to 1 ratio was good which left the height at 30". After that it was just a matter of picking inside dimensions that fit the tools.
I purchased a Forrester finger jointing blade and used the 3/8" size for the joinery. The drawers were are pinned lap joints with a hole for a pull. I sized the drawers based on a few accessories I needed to store. The door panel is a terrible piece of shop grade plywood that I cleaned up by filling the holes and using a half can of old spray paint. The door handle is a traditional ring pull. I've done a few turning projects since this was created and it's very nice being able to put all my tools away when I'm done and not have to worry about them. I now realize I need to do the same for my woodworking tools.