I'm a big fan of the Best Buy system - you pay for it when you order it online for in store pickup. They confirm your order and tell you by email when your order is ready. You have eight days to pick up. They don't have to worry about no-shows, I don't have to worry about whether the item will be available when I get there or pay for shipping.
That's pretty much it, though, about what I like about Best Buy.
Thats a good idea. But I think apple are happy that people are still buying loads in their stores even without this