::smile:: There is a pretty hefty write-up pending Mod approval over in the DIY section. I also summarized all of the other leak info I found while troubleshooting.
TL : DR - The rear sunroof vents feed into a plastic fitting. There is a neoprene gasket that can be misaligned from the factory that lets water draining out of the tube make a u-turn right back into the cabin. Also lets water draining down the back of the cab in.