Ah yes the volume problem. Well i made the mother of all f**kups and assumed that volume could be controlled from the ipod. However this is not the case. I plan on routing the volume knob to just to the right of my steering wheel so its hidden and volume control will be done from there. Im a bit of a neat freak and not a great fan of exposed cables, and the simplicity of just putting the ipod wherever i can reach it (doorcard / people in the back seat / pocket / dash ect.) was part of the plan, so bluetooth seemed the best option. And as for the other peoples music, i may put a 3.5mm socket in the passenger dash, that could look pretty cool?
Oh and once i have all the circuitry worked out, its all going into a box and into the glovebox (screwed down) to route from there. Still accessible but hidden well.