So, my solution which almost allows full use of the iPhone without any physical contact is as follows:
switch input from Manfrotto clamp attached to my wheelchair (which allows me to press switch with my head)
connected to Komodolabs iPhone interface box (which is paired with the iPhone over Bluetooth).
This allows scanning through visible fields on the iPhone with a press of the switch with my head. This can be used to perform swiping actions to unlock the phone, answer calls and dial etc
The switch mechanism does not allow use of the keyboard when searching for contacts (a bug in the software) and typing text is obviously slow with a single switch scan.
Happyfingers (PC> iPhone communication app) allows me to type text messages, search for contacts and make phone calls on my iPhone via my PC (with voice recognition) efficiently.
The restrictions with these actions are that they need to be confirmed on the phone, which I can now do with the switch input.
There are still a couple of problems to overcome, happy fingers relies on web access for both the PC and the iPhone concerned (to relay push notifications to the iPhone among other reasons), this is frustrating in the many 3G blackspots around where I live.
The second problem is that the happy fingers needs to be paired with the phone before voice-over is enabled (although this is not so much problem if you are aware of the solution).