Apple has already booked the capacity from suppliers at the cheapest prices possible for the years ahead using its cash reserves. No one can get at that price - any component for that matter. Suppliers are happy as they fill their capacity and also get money in advance - no one pays in the industry within 90 days. So Apple may be making more money in iPad 2 than 1. In the case of iPad 1 apple did not buy the display in advance. They only bought the flash chips.
If Apple owns the SOC for the dual core A5, the price for the RAM is only thing that will be extra in the die form. This could be already bought - as apple uses the 512MB RAM for the iPhone already in big volume.
So worst case BOM will be same or 2~5% cheaper than the iPad 1. LCDs are bought at 10% cheaper than even the biggest guys in industry could get. How can any competitor get that price advantage. Solid proof is that apple just throw away the faulty iPads.