Native code (C++) UI framework, awesome! Here is a more wide description from the Overview video:
Is a C++ backend instead of managed, for performance and for footprint, but, also we've taken the toolchain from the Silverlight development process so you still get all the benefits of having the two disciplines of the designer and the developer.
So with Expression Bend you are still able to design all of your UIs and all of the storyboards and animations and all the effects that encapsulate the UI are all still done by the designer and then the developer takes that XAML and instead of writing managed C# or VB they write C++ code.
Next I wanted to see how the code looks like, I've found this tutorial and a document on how to "Create a Custom User Control in Silverlight for Windows Embedded".
I don't see why this C++ Silverlight framework should not be available for Desktop, performance and small footprint are also important for Desktop applications.
This would be a great addition for Visual Studio 2010 for native developers, besides the new Intellisense based on the EDG C++ frontend. But I guess the feature list for Visual Studio 2010 is frozen, maybe for Visual Studio 2012.
If you think that having this technology brought to the Desktop is a good idea please sign this petition and spread the word.