LYONS,
The best place to start researching the project is VWnavi.com.
AFAIK or remember VW did do a standalone RGB camera. But its more complicated than you think. The OEM MK5 badge camera unit has the control unit (which coverts the RGB signal into something the RNS-510 can understand) built into it. This is one of the reasons why its massive and requires one of the wiper arms to be removed.
You COULD, go down the Passat camera badge route which doesnt require any cutting of metal, but you will need a seperate aftermarket control unit box (kufatech.de best place for this) and at present the box's dont support the guidelines you see on the RNS display.