On Calvetica's Custom Interface
Take a look at Calvetica Calendar for iPhone. This app has a stunning, almost metro-like interface and I think is one of the best demonstrations of a custom iOS interface. It’s completely immersive, and seems to use no default-looking iOS controls.
I think these types of interfaces are what Corona developer’s in particular should be inspired by. Sure there are native-looking interface widgets rolling out, but they can be customized to use your own look-and-feel.
I heard of the Calvetica Calendar app via Ben Brooks’ Review.