suprunner,
Two things come to mind.
Higher revs put out higher oil pressure. I see this all of the time on my Duramax. The oil pressure gauge varies greatly from idle to higher rpms, rising as the rpms rise.
And change that PCV valve. My 1990 300ZX started leaking oil out of the rear main seal at about 50 000 km. Not a great deal, but enough to leave a 3 inch circle of oil on the garage floor after every drive. I changed out the PCV valves (that car had two) and no more leaks. Obviously the built up pressure in the crankcase caused the leak because of the plugged PCV valves. Once they were replaced, the crankcase could release the pressure, and the leaking stopped for the next 18 years that I owned the car.
Maybe someone else will jump in with more suggestions. Good Luck!