There may be hope here. I had this problem and had to replace my engine. When I went to the local ford dealer to get a clutch and and oil filter, the parts guy told me that there was a new motorcraft oil filter with a silicon valve that maintains the oil pressure. Since the tensioners are held in place by oil pressure and the clacking sound occurs when the oil pressure drops overnight, this oil filter is supposed to supplement the original seals that keep the pressure up.
Try getting the filter from your local Ford dealer and installing it before you go and spend the money on the TSB. If it works, it will save you mucho $. So far, my new engine (used actually, with 60k miles on it) is rattle-free on startup.
Good luck!
Geoff
