The Wii U's tablet-esque controller may tout its touchscreen as its main selling point, but there's a lot more than meets the eye going into every one of Nintendo's resistive-screened revolutionaries. Patent diagrams for the WiiPad's schematics list off plenty of components you'd expect (touch panel, touch panel controller, camera, etc), however eagle-eyed patent trolls have pointed out a few less common additions to the hardware, namely a magnetic sensor and flash memory.
The "magnetic sensor," more commonly referred to as a magnetometer, measures your proximity to Magneto disturbances in a device's magnetic field. Magnetometers have been used in smartphones to find true north for GPS and compass applications, however the technology can also lend itself to touch-less, camera-less gesture input.
Flash memory, while mentioned, is not listed in any specific quantity, which makes inferring its purpose somewhat difficult. The memory is listed separately from the onboard CPU's internal memory, however, so its applications will likely be user-oriented rather than processor-oriented. For now, all we can do is wait, imagine, and dream. How many Miis will we be able to fit on this thing? All of them? The future is so bright.