Take this tidbit with a pound of salt and a pinch of skepticism, but a Japanese technology site is claiming Apple's
next generation iPad device is going to be thicker than previous versions, especially at the bottom. Translated text from the overseas blog wasn't able to explain the reason behind the added girth, though it could have to do with an upgraded display.
There are other rumors floating around suggesting the iPad 3 is being upgraded with a retina display with double the pixel density of current iPad devices (iPad 1+2 sport 132 pixels per inch), which would be one of the main selling points. It's also been reported that Apple's eying a February 2012 release date.
A retina display wouldn't necessarily require a larger chassis, so perhaps Apple is also gearing up to upgrade the iPad 2's craptacular cameras, especially since the rear-facing camera on the iPhone 4S is arguably point-and-shoot quality, and leaps and pounds ahead of the iPad (not arguable).
Regardless of the reason, the Japanese blog says the iPad 3 will still support current generation Smart Covers. If true, that means one less accessory to buy, assuming you're gung-ho to get rid of your iPad 2 in the first place.