I'm going to assume that you REALLY know what you're doing here...

There's pics of 5 and 3 volt rails here.

I don't know how much current those rails can handle. I do NOT RECOMMEND DOING THIS unless you're sure the empeg can handle it and you REALLY know what you're doing with the soldering and modding the pins on the dock and such.

All sorts of things can go wrong if you try this:

- Blow your empeg motherboard.

- Blow something else because you grounded the 5v rail on that modded serial plug on the dock connector.

- Blow something you plugged into the modded serial plug because of that 5v rail.

So um, my official word on it is... don't do this.

(Unofficially: This is a neat idea for powering non-12v GPSes and I wish you the best of luck in making it work.)