Very well done! Rated 5 out of 5 stars

Like others, I have looked for something like this. Currently running FF 10 beta 6. They work fine.

This review is for a previous version of the add-on (1.0.3). 

About your question (that was in the email but not in this comment): The scrollbar borders in light view are needed for light customizeable backgrounds only. Scrollbars background does not look like it is mixed with (light) webcontent that way.