I've been working on a model recently that uses primarily two colors, Silver Ink in the Metal menu and Black in the solid menu. It's kind of a pain to switch between them which gave me an idea. I nice feature to improve workflow would be a color menu with all the colors currently being used in the model. That way when you're only building with a handful of colors, they're all in one menu and you can easily mouse over and click on the one you need.