I had they same problem with my 06 250 ext. cab. They changed the camber by 5 deg. and it did help alot. I still think that it doesnt feel like a 36k truck but it is much better. I to am disappointed in fords quality. I think it all relates to the coil springs instead of leafs. It just doesnt control the flex of the axle correctly. After the holidays i will be putting on a better stabilizer to aid in the little bit of shimmy thats left.
Good luck with yours..