So many rumors about the Apple iSlate touchscreen tablet lately. I thought about it tonight, and I believe that the only way to make the default input method acceptable in such a large device (in landscape mode) is to create something like the following image (excuse the bad graphics please):

For the vertical mode the device might just have the right size (or not) to type with both thumbs without having to break the virtual keyboard in two. However, the “right size” can never be as good as adjusting the size of the virtual keyboard, since all people are different.