Gawker: A source who worked with Jobs emailed to say "several people had security clearances at Pixar since, in the early days, they were selling an image rendering software system that could be used to enhance satellite surveillance photographs and film. There was even a Chernobyl demo. They thought that the 'spooks' would provide a huge market."

Aiming to break into the government market on an enterprise level, Apple has submitted three cryptographic modules that are in the modules in process queue for FIPS 140-2 compliance, according to Easter. Two of the modules in the testing process are specifically designed for iPhone and iPad security, and the third is a more generic module, he said.
Apple seeks to better iPad, iPhone security via FIPS 140-2 compliance

Well, Apple certainly has come up with the idea even though they haven't yet realized it.

"Back-Side Interface for Hand-Held Devices"

Abstract:
An electronic device uses separate surfaces for input and output. One of the surfaces (e.g., the bottom) includes a force-sensitive touch-surface through which a user provides input (e.g., cursor manipulation and control element selection). On a second surface (e.g., the top), a display element is used to present information appropriate to the device's function (e.g., video information), one or more control elements and a cursor. The cursor is controlled through manipulation of the back-side touch-surface. The cursor identifies where on the back-side touch-surface the user's finger has made contact. When the cursor is positioned over the desired control element, the user selects or activates the function associated with the control element by applying pressure to the force-sensitive touch-surface with their finger. Accordingly, the electronic device may be operated with a single hand, wherein cursor movement and control element selection may be accomplished without lifting one's finger.

You just answered your own question.