I saw this process on American Chopper recently.
A guy wanted a money themed bike.
They created a sheet of money like you would see at a mint, and then dipped the gas tank and fender in it.
The tank and front fender look like they are money.
You can see it in the bottom image, if you zoom in.
Sorry I couldn't find a better one.
All in all the process is amazing and virtually any picture can be used.
Dan