I installed iOS 7 on my iPod touch 4. Here's how - YouTube
iPod touch 4G - iOS 6 vs iOS 4 - YouTube
Raffaele on Twitter: "Is this the first iPod Touch 4 running iOS 7.0 in the world? Successfully dualbooted iOS 7.0 on my iPod Touch 4. Many thanks to @nyan_satan for the dualboot
First Look: Apple's iOS 4 for iPhone, iPod touch | AppleInsider
Does the iPod touch have the same screen as the iPhone 4? - 9to5Mac
The 4G iPod touch, iPhone 4, iOS 6, and FaceTime | Low End Mac
iOS 7 dual-booted on an iPod Touch 4th Generation - A look at this unsupported feat and how well it works - Wololo.net
iOS 4 Now Available For Download [UPDATE: Direct Links and Readme File] - MacStories