C3 CustomCodeCrafters have just released their Xenon iViewer template for the iPhone and iPod Touch, bringing many of the features of the popular iPad version to the smaller devices. Full support for Retina devices using @2x images means that those with fourth generation iPhones or iPods will benefit from super sharp graphics whilst 3G devices are still fully catered for.
More info here
To see a screenshot on your device simply point your iViewer app at:
http://www.customcodecrafters.com/demos/xenon-demo-iphone.gui
For a closer look you can download a more extensive free demo .gui file from the C3 website