It's probably more like 300 iPads. However, I'm not sure this really matters as you get the cables and chargers with the new iPads and you would have to purchase new cases anyway, even it was the same form factor as the old machines.
I'm talking the classroom cart[1], so no, we don't have to buy new anything other than the iPads. If you are in a school setting and you are managing iPads lose, then you really need to get a cart. Just the theft deterrence is worth it.
