I have the same Back Ordered status on my premiere order. I actually had my premiere account representative pre-order mine for me. I asked her why the Back Order status and she advised it's because the device is not in stock at this time and it's simply a place holder at this point. When she pre-ordered a couple of iPhone 4's for my company back in July we saw the same information. They both arrived ahead of scheduled release... so I would not read too much into this or worry about it at this point. We're still 2 1/2 weeks from scheduled shipment at this point.
On a side note, long time reader first time poster, so Hello to everyone. Currently using the Inspire 4G as a "stop gap" until the Atrix arrives.