Here's my DIY. I used the following part numbers from ProclipUSA.com: 830530, 215421, 514422.
Forgive the poor lighting conditions, I was in my garage, and it's dark out! You can see where I slid up the phone to reveal the Lighting connector that is semi-permanently attached to the dock. The iPhone 5 snaps in with a perfect fit, and of course charges, streams audio as a USB device, etc.
After living with the Media cradle + iPhone 4 in my M3, I decided I wanted something different for my iPhone 5 and F30. The two main problems with putting your phone in the center armrest are the fact that you can't easily access it to launch Pandora, etc., and it is easy to forget the phone inside the car. Outta sight, outta mind! I like this much better, although it's obviously a bit utilitarian.