I recently published a new project on CodePlex called Thriple. It contains 3D components that you can easily add to your WPF user interfaces. As of version 1.0, Thriple contains my old Panel3D layout panel, and my new ContentControl3D. I have put a lot of time and effort into making ContentControl3D a highly reusable, customizable control. I’m very happy with how it turned out, but be sure to read the Known Issues section on Thriple’s Release page.
The source code download also contains sample applications that show the components in action. If you want to check it out, here’s the link: http://thriple.codeplex.com/