Eljaro,
is it possibly overfilled, or parked on a steep incline? If the
oil level is above the lower lip of the rear seal, it will leak out. I wouldn't think it is the cam plug, as there shouldn't be enough
oil to leak for ten days. Check the rear intake manifold-to-block seal, that is a real problem area, and it leaks down between the plate and block. If that's not it, you may need to pull your block plate off and inspect. Put some tracer dye in it and run for a while before you do, so you can follow the
oil trail. Let us know what you find.