With the compression numbers you have, I think I would be looking at an intake gasket failure, either the bottom gasket, or the actual intake gaskets. Its got to be pulling oil into the combustion process, the compression numbers you have means its probably not coming by the rings, and that is a lot of oil coming through the valve guides, even if the seals are nearly gone.
Two other possibilities come to mind.
1) Somehow the oil returns to the pan got partly plugged up and the oil is sitting up in the valve covers.
2) Oil is running out on the ground from someplace, Oil sending unit maybe? Gene