Thanks for the advice and reassurance guys. I'll let The Seep hang out for a while. In the meantime, hopefully, Ford will come up with a better fix so that when I do get the head gasket replaced, The Seep will be gone for good. Maybe by then Ford will also acknowledge the significance of this problem on the '99 5.4L and extend its powertrain warranty (I just don't feel comfortable with the idea of having my whole engine pulled apart to exterminate The Seep when the rest of the engine is out of warranty - I hear they pull the cab off the truck to get to the head gasket)! Pretty Scary!
-JM