Hi,
I had the same thoughts... what I found out from the local Pioneer (Israel) is the following:
1. The 8400 will get some kind of an adapter to work with iPhone 5 (iPhone 5 outputs HDMI video while ipone 4/4s outputs composite video), and it won't be just a cable, it will be some kind of converter to change the iPhone5 HDMI output to composite video, probably will cost at least a 100 USD.
2. They will release around April 2013 (they said it will be in by June for sure) a new unit called 8500 which will have HDMI input and hence would be connectable to the iPhone5, would still req