I've had a go at porting a Windows Phone (C#, XNA) game I was working on last year. I've used the latest G3D builds and I thought you might like to see a clip -
http://www.youtube.com/watch?v=X4fxfEsunsQ. Obviously this is a *very early* hack together, and I know that I am only scratching the surface of what can be achieved with the rendering, but I was pleased how quickly I was able to put together rudimentary game state management, user-input, UI and rendering - I'm nearly ready to start thinking about my G3D-based game lib as a weapon of choice for next year's Global Game Jam... ;)