Disclaimer: I haven't read the post; I can't because the site isn't loading for me. Instead, I'm replying to the OP.

I would be very surprised to see this. I contribute to Colloquy — An IRC client available for Mac OS X and iOS (iPhone and iPad). Having three separate UIs aside, the shared code between the projects doesn't go through the same build steps. It cant, because iOS doesn't allow third party dynamic frameworks to be loaded; they have to use a static library instead.

In the case of Angry Birds, if you take the .ipa from iTunes and unzip it and then run otool -l on the binary, you can look at the frameworks it uses.

The iOS-specific frameworks it uses are: UIKit, OpenGLES, MediaPlayer and GameKit. GameKit could likely be ported fairly easily. MediaPlayer with a bit of work, could be mapped to QTKit. OpenGL to OpenGLES, I can't say; I don't know anything about either. And UIKit? Mac OS X has to run on Mac Pro's and iMac's as well. Which may or may not have a multitouch device attached. UIKit would be a kludge with multitouch trackpads, and downright useless without one all together.