My head was trying to absorb too many new concepts yesterday so as I diversion I thought I'd try and redesign the Indigo Touch icon. I actually thought I could replace the icon inside the .ipa, i.e zip, app package and re-sync to the iPhone/iPad to see the icon on the home screen, but it doesn't work. I think it's something to do with the re-zipping, and I can't be bothered to figure out why or to install Xcode to see if that helps.
Nevertheless, I thought I'd post it here anyway - my, albeit still a bit rough, mockup of an iOS 7 inspired Indigo Touch icon.