I dont think the price is that low. If you look at these cheap (and smaller) (E-)IPS panels that are popping up (NEC EA231WMi 23"for 300 euro, dell's ips for 200 or samsung c-pva for 200) i think its pretty obvious that its possible to produce an inexpensive screen. The computer on the back might cost like 300 so I think there is still a decent margin for apple