Any native extensions for iBeacon on iOS and Android?

Sure is, complete cross-platform, Android/iOS, iBeacon interface. You can find it here:

http://distriqt.com/product/air-native-extensions/beacon

>> Moved to here: distriqt // air native extensions

Distriqt announced their ANE for iBeacon on Facebook, but I don't know if it is available.

Here I found a ibeacon ane for Android

http://compass-interactive.com/ibeacon-ane-android/

Here’s one for iOS:

http://www.caffaware.com/archives/469

I didn’t search for long, there may be others.