OS X looking WPF/E sample has popped up on the MSDN WPF/E forums.  This one isn't as good as the vista.si sample and still has a ways to go, but it is impressive. 

One quick suggestion to everyone working on a WPF/E incarnation of an OS, use the new Downloader object to get data to your app.  This allows you to show progress UI to your users and make the app appear much more lively.  Click the image below to run the sample.