Hi! I've thought of doin the same thing and didn't want the cables showing. I know it's an arduous task, but is there room to feed the cable through the same hole as the aerial ? I admit this means making a modification to the aerial foot (I just made that word up!) to it would sit over the lighting cable but at least you wouldn't have to drill into the roof. It's then just a question of removing the head lining and feeding the cable across and down the inside of the A pillar trim.