OJ actually supports the ability to Theme objects which makes it much simpler to create design abstractions like you're talking about. It was inspired by the Bootstrap approach for customizing the look of different elements. The basic notion is OJ creates a CSS class that you can add and remove from an object to change its look. This can be done in a separate file (or even plugin) for designers to configure separately.

Here is a JSFiddle I made to demonstrate. This isn't even in the docs yet, so I made this just for you=).

http://jsfiddle.net/evanmoran/RmM96/