Here’s an interesting Stack Overflow question from a web developer trying to differentiate between an iPad 2 and an iPad mini.
Oh, fuck off.
The poster’s justification is that proper design adjusts the size of hit targets (buttons and links). You don’t need to dynamically resize hit targets - Apple has not included a way to distinguish the devices because you shouldn’t. Just make everything at least 44 logical pixels (or points in Objective-C) wide and tall and it will be usable on either device.
Follow the rules and don’t fuck around. Can I have that 500 point bounty now?