[identity profile] meico.livejournal.com 2010-08-17 06:27 pm (UTC)(link)
It is like an iPad, but with a special set of mechanical keys cleverly placed on top. The keys importantly have windows that let you see unobstructed down to the video surface below...

Someone industrious could make a mechanical add on for an iPad and then use the iPad/keys combination (and some software and interfacing) to do exactly the same thing.