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 (188.8.131.52-signed).
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.