Ok guys, headgasket 101 here. If the engine has an overhead camshaft setup, IT MUST RECIEVE oil thru an oil galley to lube the cam bearings. Years ago, external oil lines would be ran, but now and its been this way for a long time, it is ran from the block into the head, and it passes thru the headgaskets. You will see multilayer steel gaskets on these apps, just as seen in that pic above. They can leak oil, and it happens alot. Look up 1997 Ford 5.4L oil leaks, they leaked in the same area as the OP's. The oil return could be easily be where the timing chain runs, and the front of the head has holes to allow it. Cant tell you, as I dont have one in front of me. Look at the gasket pic, and look at the ear that juts out on the far left. That will be the rear of the head, closest towards the fender. Notice two round holes, one slightly different in size? That one that sets away from the rest of the holes is likely the oil galley hole, and is right about where the OP has a leak. It most likely is a head gasket leaking oil, so let them do it, and get it fixed. They have to change the oil again, so tell them to get the fill amount right this time. Dodge Neons, Hondas, etc all have had this problem, so its not an isolated issue.