Can a phone pretend to be a Bluetooth keyboard?

Question

It seems like it would be super useful if an app existed for iPhone/Android that emulated a Bluetooth keyboard or mouse. e.g., you turn on the app, and suddenly you can type on

Answer 1

The public iOS APIs do not currently appear to expose any functionality that would allow an app to make the iOS device to appear as a generic keyboard HID on Bluetooth.

However, iOS apps (iOS 4.2 and later?) can use external Bluetooth keyboards for input.