If it's your rear main seal, eventually your gonna have to put a clutch in it anyway. It's getting soaked with oil.
Try and trace down exactly where it's coming from. Like toynorcal said, it could also be the rubber cam plug at the back of the head. That's an easy one to replace if that's where it's coming from.
As far as your tcase, where is the leak at? If it's where the tcase bolts to the tranny, that's a pretty easy gasket to change. (unbolt d-shafts, pull out shifter, unbolt 6 tcase bolts, slide it out then reverse)