When Nintendo announced the Wii U, people were surprised it would only support one of the unique touchscreen controllers at a time. While no official statements have been made indicating this would change, an anonymous tipster alerted Develop that Nintendo was close to overcoming the technological limitations behind this and that the Wii U would support two controllers at a time.
Develop's source found this information within the Wii U's codebase, and also was careful to note that there was no indication that supporting more than two controllers would be possible. This could really open up multiplayer games — having the touchscreen to hide your Mario Kart inventory from the competition would be awesome — but Nintendo's keeping everything under wraps for now. With the launch more than six months away, at least, we may be waiting a while before we get official confirmation.