About three or four years ago, I was playing around with a concept I called Bricks. It was a way of factoring drawing operations out of UI components to make it easy to create new looks. The drawing operations were encapsulated into objects called Painters. I was doing it in Squeak using Morphic. It looked like this: 
It must have been a good idea because I just ran across something similar from the Java Swing people.
So I’ve decided to dust it off and pick it up again. There have been a lot of changes in Morphic and I’ve given up on reworking the event deliver system, choosing to work with Morphic’s system, warts and all. I still think splitting drawing and layout will be valuable.