I found that rattle and silenced it.
My rattle fom hell turned out to be the threaded connection between the power window machinery and the door structure. The hex head screy is located to the left and slightly lower than the speaker. (Mine was on the driver's side but I am sure the passengers is the same. Access to the screrw is blocked by the factory installed sound dedening material affixed to the door. I was able to see this connection with a mirrior I held in the door while I felt around shaking things and making them squeek etc. It may be the same rattle that is bothering you. Let me know if this is the case and I will tell ford about it. All I did to fix it was a little tightening with a 7/16 socker wrench.
Good luck with your rattle.