Need advice on Shortblock...

[MustangDanny]

I have a oil leak on my shortblock. I'm pretty sure that it is coming from the rear bearing. About 6 months ago I put a new rear main seal in when I put a new tranny and clutch in. I am 99.9% sure that I put in in correctly. But I think that oil is still leaking from that area. Is it possible that the bearing (pilot bearing?) is leaking? Or is it more likely that the oil pan gasket is leaking? A couple weeks ago I degreased the whole area and put the car on a lift and ran it for a while at different rpms to try to see where the leak would come from. I noticed it start to leak from inside the clutch area, behing that plate that covers the flywheel.

So here's my dilema. Do I rebuild the shortblock (or maybe a new one if my income tax check is nice enough), or do I just have that bearing and seal replaced? Has anyone ever done this or had it done? How much did it run you or how hard was it for you to do? If I don't have to rebuild the shortblock now (and can wait for next year to do that) then I can spend money on chassis, suspension and maybe even heads and cam.