For the most part, all the UI elements are now active. Certain sub-menus have yet to be activated (like font settings and sync), but I was surprised to see that features like settings import, content settings, and clear browsing data were now live -- just 8 days after tabbed options arrived on the Dev channel.
So why move everything into tabs, anyway? Once Google has everything sorted out and running in-tabs, future changes to Chrome's UI should be easier to implement across different platforms. Since it's Chrome itself rendering things, developers won't have to worry as much about a change looking good on Windows while breaking something on Mac, for example. The switch should also lead to a more consistent experience across Chrome's entire user base (pretty much the opposite of Apple's approach with Safari).
Curious to see tabbed options at work? Check out the video after the break (I recorded Chromium, but you can test in Chrome Dev and Canary as well -- just add --enable-tabbed-options)!