Many customers may end up disappointed.
We've got breaking news here, straight from the mouth of the manager of an Apple Campus Store. He claimed that every Apple Store in the region only received 1/3rd of their expected shipments. This particular store received ten models, all WiFi-only. The manager was unclear as to whether or not this shortage applied to all Apple Stores, or merely campus stores.
The Best Buy employees I talked to reported 4-5 models per store. From what I've been able to gather, no store has more than fifteen models. The Apple Stores appear to have significantly more, but it is clear that first-day supply will be extremely constrained. If you aren't in line now, you've probably missed the boat.