Wish I could help, Nick. I remember you and I discussed the vibration problem quite extensively last spring. I've replaced everything imaginable in my car, and I've gradually removed almost all of the vibration, but not all. Luckily, the vibration I removed hasn't returned (yet), but the small amount I have is not consistent. ONe thing I found on mine (that I had not really suspected) was a worn front end-link. This was letting the tire bounce and vibrate slightly. Don't know if this would have any relationship to your problem or not.
Good luck. Maybe sometime when you're through Atoka, we can compare symptoms of our cars, and see if we've got the same problem.