A developer under the username "businesscat2000" has posted a video showing iOS apps running on the BlackBerry PlayBook. The videos were first posted in the CrackBerry forums and were immediately challenged by CrackBerry who wanted to see proof that the video was real, and they got it. The developer performed some live tests on iOS-only apps running on the PlayBook.
The developer explained how he did it in the CrackBerry Forum:
The CPU isnít emulated on Playbook (though it is on Windows). It works very similarly to how WINE works to run Windows applications on Linux. The app binary is mapped into memory and imports are resolved to point to my own implementation of the various APIs needed. iOS actually uses a few open APIs already, which Playbook supports just as well (GL ES, and OpenAL). The bulk of the work has been in implementing all of the objective C classes that are required. The ARM code of the applications run as-is Ė the armv6/v7 support on PB/iDevices are pretty much identical, and the code is designed to run in USR mode. No SWIs, GPIO accesses or any of that kind of shenanigans.
I'm not sure why anyone would want to run iOS apps on a PlayBook, but it is a nice feat.