Mystery oil leak

Alright I've been leaking oil since I bought the thing. I have a 90 xj with the 4.0. At first it was just a little drip when I would shut off the engine, so I replaced the rear main seal. Then it got worse. Long story short I've replaced the rear main twice and dropped the oil pan even more. Last time I made sure everything was golden. Looking closer, the whole right side of the engine is wet with oil. I recently replaced the gasket on the valve cover, so I don't think it's that either. Also had the o-rings on the oil filter adapter replaced. I'm wondering if it could be the head gasket. I haven't seen any coolant in the oil, but I am losing coolant somewhere, another mystery. I also don't think I have the power that I should. I'm going to try a compression test on all cylinders in the next couple days. Has anyone ever seen something like this? I've always thought is the head gasket went it just went and you weren't going anywhere. I only have 123,000 miles on it but it was formerly someones vehicle for their vacation home so probably sat around a lot. any help would be appreciated, I'm running out of hair to pull out...

Head gaskets don't always just "go". More often than not they start leaking first and that may be what yours is doing. The oil galleries are on the passenger side of the block and if you're leaking oil through the head gasket, that's where it'll be.
Clean the engine and then look out for new oil leakage. Then it'll be easier to find out where it's coming from.

Oil does not generally leak UP, so go to the highest place the leak is and look from there. Also look at your plugs, they will tell a long story if you now how to read them.
Heres another trick, if your ccv system is acting up loosen your oil filler cap half way so it's loose, then run a strip of duct tape across to hold it from falling off and drive like that for a few days. This will reduce any CC over pressure that may be forcing oil out of any seals.

Just some ideas...

check the distributor seal