Looks like it's back to store pickup only again. I must have hit one of those magical 1-2 minute windows of re-availability people mention so often, as I bought it about a minute before making that post. I guess they really do happen sometimes.
Just went to two Best Buys in SoCal (Tustin and Irvine/Lake Forest), missed getting a copy of Kirby by 2 minutes, failed to pricematch at a nearby Walmart (they had it in stock, though), then came home and found it's available to order for delivery from Best Buy's site again. Good times.