Availability elsewhere
To see how it compared to Best Buy here is what some other retailers are reporting on their web sites this morning, as of approx 9am PT.
Amazon: Both in stock with only 5 of non-SSD left at present;
MacMall: Both "Generally in Stock";
MacConnection: Both in stock estimated to ship today;
B&H: Both in Stock;
OnSale: Both "Generally in Stock";
J&R: Non-SSD out of stock and SSD shipping in 3-5 days; &
MacWarehouse/CDW: Non-SSD "Call for availability" and SSD in stock.
If anything, without being able to compare these to another point in time, it does look like that there is a shortage of the non-SSD MB Air at present but not to the point where current stocks are exhausted.
I'd hazard a guess that over the next month stock levels are going to drop and shipping times increase as we get nearer an October announcement and we'll see the increased rumours usually seen before new hardware is released.
Anyone with more experience of this care to weigh in?