An update following my DT appointment...I explained the situation, and they inspected the tires for balance, and looking for any physical deformities with any of the tires. They said none of the tires were out of round, or deformed in any way, and one tire was 1/2 ounce out or balance. They rebalanced that tire, then rotated the tires. I immediately took the car out on the highway and accelerated to about 75 MPH, and the steering wheel shake was completely gone. Before, the shake was very noticeable at 70 MPH. THIS MAKES ABSOLUTELY NO SENSE TO ME. The tire that was out of balance was on the rear, which means it was on the front, then I rotated it to the rear. This made no difference in the steering wheel shake. This tire is now back on the front after they rebalanced it and did the rotation. If any of you can make heads or tails of this, I'd like to hear your thoughts, because this makes no sense to me whatsoever...