Those prices are in line with my initial guestimations. Isupply says it only takes about 326 dollars to make an ipad 2. That's with the 3G components. Considering every model wont have 3G and the screen is much smaller I can see Sony selling it with a very small loss of 25-50 bucks per console. Maybe even break even if they got a good enough deal because of the quantity on the CPU and GPU.
Hell some places have the bill of materials cost at 270 which is much closer to the original ipad cost estimations.







