Did you check the chain tensioner seals? they all leak, they are between the valve cover and the head itself, and the seal along the head tends to leak.
-2001.5 S4- I've replaced the valve cover gaskets twice now within 5k miles...Before the last replacement I also replaced the entire PCV hose system (thinking that I was just building to much pressure in the crank) but I still seem to be leaking oil from the back corners of my valve covers... my camshaft seals still look good, and it appears pretty obvious the oil is coming from the valve cover. Besides the PCV system are there any other check valves that could be forcing pressure into the valve cover? Someone told me that faulty valves could be doing this??? Valve covers bent??? I didn't torque them down but I went in a star pattern until every nut was *tight* (I also used silicone sealant)...lemme know what you think, thanks