I’ve been fighting this thing ever since Florida, 2006, and I have finally defeated it.
I pulled the oil pan off the car again (front (of car) motor mount must be removed to do that, btw) and that showed me the cause of the leak: I used JB Weld to seal the oil return line bung, and I manged to miss a huge spot. So I mixed up some more JB and sealed it up. The car ran for 20 minutes and then sat for four days and no more oil leaking. Or, at least, if there is, it’s a very minimal amount like a quarter-sized spot after four days. I may have boogered up the return hose trying to get it off the oilpan…
I also discovered that the oil smelled like gas and there was some grey sludge in the oil pan. I cleaned all that out, and I suspect that the gas is from either blow-by or the no-start conditions, and the sludge is from not running enough to reach normal temp. I’ll keep a close watch on that.