Hey man, I just got my truck inspected in British Columbia, I just moved there. But anyways, I told them my concern about the oil leak, and that I thought it was the rear main seal. The took a look at it and told me its probably not the rear main seal, they said they have replaced those seals before on similar trucks and my truck isnt showing the same symptoms.
They said that it is most likely the oil pan gasket, have you looked there yet? I figure that the gasket is leaking near the back of the oil pan, and thats why the oil is leaking from what looks like between the engine and the transmission. Worth a try at least. I'm goin to try to replace mine, see if that stops the leak..