I just sent a proposal to Allan about an extension to the Syntax system to allow for global repositories for styles and colors.. essentially, this would allow the syntax files to use named items for colors and styles, and the user can then change everything from dark to bright very easily. This is similar to what several people proposed here. The mail I sent to Allan is in danish so I won't quote it, but.... it's quite similar to what Brent Bourgoine suggested :-).