Here are the details:
As I mentioned previousely, I constructed the prototype using black cardboard but I just got lazy and end up using it permanately. The top piece of carboard is covered with a piece of textured black plastic which I cut out from the back cover of a portfolio folder. The dock itself came with my 3rd generation iPod and I painted black to match the plastic cover. The 3.5mm mini-jack is from the PIE adapter connecting to the back of the headunit. I was gonna hardwire the power but got lazy and just used the regular iPod charger plugged into the 220 plug inside the center console. It takes some space inside the center console but I can switch it on the off without any modification.
Let me know if you have any more questions.