We all have that problem and the real reason why is allocation, the distributor, and apple. They only look at the register traffic. What they fail to grasp is the fact that the guy asking "Do you have iPad 2's?" is one of many that would be a customer to add to their little number but because we didn't have it, he didn't buy anything so it still looks like you have no customer traffic for it. It is a vicious circle.
If your store is still having problems getting some of that merchandise in I suggest this:
I took the initiative and started keeping my own list of customers that wanted a certain item (for us it was the iPads)
in a 1 month period I had 250 customers that had either called or asked for one. I then preceded to multiple that times the lowest price for an iPad, then presented the total sales and customers we could have had to the assistant store manager. A couple weeks later, 156 iPads showed up out of nowhere and they have just kept coming in. I later found out it was because my information was sent up the ladder to SD and they finally realized "wow this small store could really move theses". No one realized everyone was coming to our small store before they were going to the bigger AAFES stores that were in our area until I provided my evidence to back up my complaint.
Yeah it will be extra work for you but believe me, it felt good being able to say "YES WE DO HAVE THEM IN STOCK" after months of saying "No, we don't carry it".