Toyota Repair: 1996 Camry oil leak, engine oil leak, valve cover gasket

Question
1996 Camry with 123k is leaking oil on the driver's side of the engine.  The leak deposits about a 5-6 inch diameter puddle after 30-40 minutes of driving.

I've had the following done with limited to no success - oil pan seal, valve cover gasket, and rear main seal.

I'm getting tired of spending money with limited results.

No leaks are visible from above the engine and can't seem to find any from below either.

What's left to do?  Any ideas?  

Thanks.

Answer
The best advice I can give you is to not have any more repairs done at your expense, it seems that the repairs that were done were either not done correctly or misdiagnosed and the real reason for the oil leak has not been located, I would recommend that you either go to the toyota dealer or another repair shop that can add a flourescent dye to the engine oil and then drive the car for about 100 miles and have it checked with an UV light to pinpoint the leak, it could also be a transmission leak, axle seals on transmission do cause oil leaks. If no engine oil leak can be found I would recommend having them check the transmission axle shaft seals or possibly a torque converter seal, in any case you need someone competent that knows how to diagnose oil leaks look at this, it sounds like whoever has been working on your car doesn't have the ability to do that.