The only real missing piece is the audio I/O, but that is not too hard to do. Ideally, the rjdj crew would release their audio I/O code to be included in Pd-vanilla and we should share the work of maintenance and improvements. But that's not the only way to get it done. I'm here at Mobile Art & Code talking with Memo Akten and Zach Gage, the two openFrameworks/iPhone developers, and they have open source audio code that should be pretty easy to plug into Pd. SuperCollider has been ported to the iPhone too, but I haven't been able to find that code.
as I understood, openframeworks is using rtAudio, which is certainly a good choice, as it is designed for real-time. But why portaudio (the current audio implementation in pd if I'm right) would not work on an iPhone ? loic