Re: 21" screen?
>> "White's mole claims the next iPad will sport a 7in screen..."
Why and how? This implies that Apple will either dilute their brand by offering two very similar models (one of which strangely fits too closely between the iPod Touch and the "normal-sized" iPad); or somehow admit that their best selling product so far is designed wrong by a too big a screen, and shrink it in its next version.
The former would be confusing to the typical consumer because the difference in size is minor, compared to iPod Touch to iPod Nano, or iPod Touch to iPad. The latter is extremely unlikely do to the popularity of the current model and the un-Apple-ness of the option.