Auxo the awesome Cydia tweak which transforms the iOS app switcher has now been released for iOS 5.1 and above. You can read more about the tweak here.
The tweak was at first available only for iOS 6. But the developers quickly saw the demand for it on the iPhone 4S which can only be jailbroken at iOS 5.1.1. They very quickly worked to get it working on both versions of iOS.
The wait now is for the iPhone 5 to be jailbroken, which this tweak was primarily made for, because it has a larger screen.
The tweak is available on Cydia right now for $1.99.