The vibration debugging continues!
I sent the front drive shaft back to Tom Woods. Drove around without it for a week or so and had no vibrations. They say there was some play in the CV ball and some damage on the trunions of the joints in the CV. They changed our the CV socket flange, CV center housing and both joints in the CV.
I got it back, put it on, and it vibrates still.
Since that time, I've put in new HD steering rods and new HD panhard rod, and gotten an alignment done. Still vibrates over 30mph and vibration ceases when letting off the gas.
Any other pointers out there? I'm stuck. Doesn't make sense that it stops vibrating when I take the shaft off, if the shaft is ok. Maybe I'll take it down to an independent shop and have the balance checked as a last resort.