I picked up the ProClip iPhone 4 dashboard mount, works well if anyone is looking for a similar mounting solution. They use a two part system, a clip specific to your vehicle + a device mount. They have a few iPhone 4 specific mounts, I went with the Adjustable Mount w/ pass Through connection. It was a bit pricy ($110) for both the clip and the mount, but it's a very custom result. I'm pleased, handy for using the Tom Tom app.
Pictures below (installed in my Audi A3). The charger's not included, I had that already.
Pictures below (installed in my Audi A3). The charger's not included, I had that already.