There are dozens, if not hundreds of Android tablets, and concepts coming in the next 18 months, not to mention Windows 7 mobile etc
The Windows 7 mobile platform is just as closed as iPhones and iPads, and Apple is trying to have Android shut down by the courts. If they get their way, there will be no viable open alternatives for mobile computing.
Most of the scenarios I envision for laptops involve typing without a desk (thus the need for the supporting base of your lap.) I don't think anything is really replacing them for these.
The Windows 7 mobile platform is just as closed as iPhones and iPads, and Apple is trying to have Android shut down by the courts. If they get their way, there will be no viable open alternatives for mobile computing.