Apple seems to be quite happy to talk about the possibility of an iPhone in its patent applications.
This patent application covers what appears to be the latest generation aluminum iPod- though it says the manufacturing system could be used for mobile phones, handheld computers as well as iPods.
The interesting feature of the application is the [...]

The Ultimate Customisable iPod/MacBook/Tablet- add the controls and software and make it a phone or what ever you want.
Apple has just filed a new patent application for the adding of physical controls (like buttons or sliders etc) to the touch sensitive surfaces of electronic devices. Apple seems to propose that you take a ‘blank’ iPod [...]