Check the tires...or borrow a set of rims and tires to check it.
I've got an 04 AWD. Stock 17" rims w/ 265 tires, no lift or torsion tweaks. For the last three years, I had a vibration from 45 on up. First, I had the left ft. half shaft replaced, it didn't fix it. Then, I thought it was the front driveshaft...it clicked when braking and accelerating from a stop. It was bad, but not the source of the vibration. Turned out to be bad belts in two tires. The tires had been balanced numerous times and were always fine...but one leaked down slowly and the other developed a bulge. Two new tires and the vibration was gone.