Another possiblility for you that's worth a check. Strangely enough, one of my mates called me yesterday to tell me he's finally sorted out a bad vibration he's been having on his Focus, although not the station wagon. He'd checked suspension, all motor pulleys and stuff, but it was still there. At a different Ford dealership, some serious diagnostics went on, and as they were about to give up, someone suggested a look at the engine mountings. The rear one was cracked and the one on the cambelt side needed replacing. This was overlooked due to a plactic cover being on the mounting which makes it look fine, but removal of the cover showed the rubber underneath to be soft and torn. It wasn't a cheap fix here in SA, but two new mountings and the car is once again smooth. Maybe it's worth a check on your car.
