Using the Hybrid Core, I've built my first commercial WordPress Theme, called Pictography. See a live demo here: http://photos.michaelwender.com/.
The theme features a home page Image Carousel which displays any and all featured images from your posts.
In addition, I've added code to the theme which lets users post "featured images" from WordPress for iOS or WordPress for Android (currently a limitation in the WordPress XML-RPC prevents the apps from doing this themselves).
For more info on the theme, including a 60sec trailer, you can see the theme's info page here: http://www.wenderhost.com/themes/pictography/