I have the samle problem with my 2007 Expy Max (Canadian version of the EL). The dealership has acknowledge that there is a vibration but won't do anything about it because they feel that there is nothing they can do... I've asked to explore other possibilities, like balancing the drive shaft, but they have said that because the truck has only 70K km they wouldn't be able to get Ford to cover the warrenty. I am going to another dealership to see if they can diagnose the problem!

Good luck with the lemon law!