Chinese website NextMedia / Apple Daily published this picture:

On the lower picture there would be from left to right the original iPad, the iPad 2 and the new iPad 3. We can see that the camera lens is bigger than on the current model. It would be the same 8MP sensor as on the iPhone 4S, which would make the iPad a good camera, left aside the lack of flash and the size of the device.
It would seem that this new model could be a little bit thicker, probably to have a bigger battery, which would provide a better battery life or at least keep the current one, since the HD display will need more power for backlighting.
It is amazing to see that Apple has become unable to keep complete secrecy over the details of its next mobile products, mostly because of the growing number of its sub-contractors. The company seems to have given up on that battle, while keeping a firm lid on software development, mostly based in Cupertino as with Mountain Lion for example.
