I saw that programmatically turning bluetooth on and off was a "private api" thing in previos versions of iOS that would get an app rejected from the apple itunes store.
But in iOS 5, I am aware of previously private things that are no longer private, such as programmatically changing screen brightness. Doing this will no longer get your app rejected in itunes with iOS 5, so I am wondering if this other things were available publicly, like the bluetooth adapter.
CoreBluetooth is publicly available in iOS 5. Unfortunately it only works for new Bluetooth LE (Low Energy) devices.