Android apps are already up and running on the BlackBerry. Now, at least theoretically, it would be possible to use iOS apps on the Playbook. So says the developer of “Bubble Wrap”, pointing to YouTube videos of the Brine iOS emulator for Windows and Playbook.
The Windows version runs on an ARM emulator and provides the necessary environment for running Playbook-only versions of the iOS apps directly on the tablet. If this really works for all the apps as well as it does in the videos below, then that would be a tremendous piece of software.
But it is not to be expected that iOS apps will run directly and officially on the Playbook like Android apps. Apple would probably react very badly and pursue a legal course of action. And because retaliation is expected, RIM would probably not even distribute the Brine iOS emulator on the BlackBerry App World.