The mod I do is to the existing harness in the 2010 car, thus I need the car with me to facilitate the mod. I have done this to my car and two others quite easily ( I am an elec. tech)
HOWEVER, the only reason I have done this was because I am somewhat handy with a soldering iron and because Brian was experiencing a family loss at the time I wanted to do the mod. I bought his camera harness kit first and was extremely happy with the quality and build, and would have purchased the NAV/Camera/DVD hack too if it would have been available at the time.
BUY BRIAN'S MOD! It's worth every penny....
Having said that, I am happy to do mods like this for materials cost plus a coffee to anyone in the Edmonton area, lol!
Otherwise, NAVTool for 2009 cars plus the soldering hack:
2010 Hack HERE. Just use the 2009 FSM for the correct pinouts for power and VSS. The DVD would have to be connected via the NAVtool and the Camera would activate thru the Navtool as well.
As for building a harness to connect a 2010 head to the 2009 vehicle...
.... I don't know. The screen is different too....