I ordered the Acer tablet from Best Buy at 11:00am on Nov. 27 (ship to store). It was originally supposed to be delivered to store by Dec. 5, but I received an email shortly after I placed my order saying that it would be shipped to store today (Dec. 13). I haven't received any more notifications from Best Buy or any shipping carrier saying that my item was being shipped to store, or has been received by the store. I just called Best Buy's 888 number, and the woman said it is backordered with no time estimate on when it will become available. My next step will be to call the store directly.
FWIW, if you received a notification that it was currently being shipped to store, you won't receive notification again until you get the email saying that it was ready to be picked up.