Actually, Paige just recommended that he study real cabinets, which I think is a great idea for somebody trying to decide what they want. I've always recommended to that people trying to design artwork from scratch.
Right. certain things tend to get implemented certain ways over and over again among real cabinets. This forms a sort of general set of design rules for arcade cabinets. While not every factory cabinet adhered strictly to these unwritten design rules most actually stayed pretty close. When you stray too far from the formula the cabinet starts looking wrong, and many of these wrong looking things actually make the cabinet worse in some fashion that is more than just cosmetic (strength, stability, reliability, functionality, etc).
Things the community pretty regularly gets wrong include.
#1. Basic dimensions of the cabinet style they are building. This includes trying to build a cabinet with a separate top and bottom section.
#2. Distinguishing between the type of cabinet that has a separate control panel box, the type that doesn't, the dimensions of those boxes and how those control panels should match up with the cabinet and the box.
#3. Monitor installation, including how to make a widescreen monitor still look good in a cabinet style designed for 4:3 (for those that insist on using them).