For the past few years I've been involved in the FirefoxCSS community, where like-minded people enjoy "Pushing the limits of the Firefox Browser through the use of CSS."
One of the reasons I had switched from Safari to Firefox was to have extensions among other features, which makes Orion exciting!
I had to work on a theme for Firefox to make it look like safari
The feature I am suggesting is to allow something like userChrome.css of the browser to be edited by the user.
I understand Webkit may work in a different way to Firefox and Chrome in terms of customisability, however would like to see if this is possible, or to find out what level of theme customisability may be included in the future?