Apple gets tricksy.
Apple may have a smaller, 7" iPad ready to compete with the Samsung Galaxy Tab. Shanzai reports that a 7" tablet is "well underway" and is actually "a finished product" at this point. Five alternate designs have also been released around Shenzhen, in order to help hide the real iPad's design.
Somehow, Shanzai's source learned that the final design will be very similar to the iPhone 4, rather than the current iPad. This isn't much to go on, but it's another bit of evidence that Apple may have some ideas for a different slate form-factor due out in the near future. Of course, I'd expect them to wait until the Tab has either succeeded or failed miserably before trying their luck with a smaller screen.