Just had a shadetree mechanic fix the leak for me. (I'll caveat by saying it's only been a day since the repair, so I'm driving it in order for me to look again later to verify that there are no leaks.) All along I thought it was the rear main given the discussion on here and even finding some threads that had pictures of my exact same oil drip (just off the inspection plate on the bell housing and the passenger starter bolt on the oil pan). Anyway, in my case, the oil pan gasket was bad. He showed it to me along with the old rear main seal and the old rear cover gasket, both of which were in good shape, but the oil pan gasket had torn on the driver side where the oil coolant lines would run if I had them in my Yukon. I suppose this was running to the opposite side of the engine and then gravity was doing its thing. When I cleaned it off late last year, I saw the problem developing on the passenger starter bolt first, which was why I thought it was the rear main.
All this is to say, if you have a similar occurrence, go ahead and replace the rear main seal, rear cover gasket and the oil pan gasket. The mechanic said it was a pretty tough job that takes a couple of people as he had to drop the transmission and take out the transfer case to get to the oil pan gasket since these vehicles are AWD.
