work out the dock connector so that connects with one hand then pivots into the pocket where the ashtray was. I think the connector will have to swivel and have a spring on it so that it has some tension keeping it tilted at 30 degrees up from horizontal so you can slip the Iphone onto it easily.
You can get the phone into the space and still have room for the ashtray cover to go over the top for a semi-permanent Ipod install but since I am going to use my Iphone I will be taking it in and out when I leave the car I am working something very similiar to your photo shop picture.
I will be using the Iphone for it's 3g connection to provide wifi for the car computer with touchscreen.