Now that I am in the acceptance stage of mourning, here are a few more details...
Driver was solo but easily got the set into the house and as I said earlier box looked absolutely fine.
He was eager to leave, but agreed to stay while we unboxed it. He and I both examined it pretty closely (I thought) and I was so psyched because it looked gorgeous. Thinking all was well, I signed for it, but still wrote "subject to final inspection" since it was still resting in the box and I hadn't powered it up.
As soon as the driver left, I got a flashlight since I remembered people saying the cracks could be subtle, but it had looked so good to me that I had no expectation to find anything. I immediately saw a crack near the edge of the upper left panel, then another in the lower left, and finally one in the lower right. My inexperience clearly showed by not using the flashlight when the driver was present but I had no idea how subtle these cracks could be. Hard lesson learned -- hopefully others can benefit from my experience and not make the same error.
Per Dave at Satellite & Sound, the supplier (which appears to be called Electrograph, Middletown, NY) had only had 1 bad unit of 20 in prior shipment of these units so I think it is just lousy luck.
Good news is that Dave had another unit set aside for him, which should be shipping out to me today. Hopefully, it will arrive early next week.