It looks like at one point in time, Nintendo intended to release a gaming mobile phone and has even filed a patent for such a device in November 2001.

It took the USPTO until June 2006 to issue it and chances are that Nintendo has given up producing such a phone completely by now, otherwise some sort of rumor or supposition would have appeared.

From the patent it looks like Nintendo was planning a mobile phone that runs two chips, one for games and one for the other mobile functions.

The mobile phone has been described as being an "Electronic apparatus having game and telephone functions", but since it's Nintendo we're talking about, it was probably meant to be more of a gaming device with added mobile phone functions.

While nothing leaves us believing that Nintendo is actually still considering to release a gaming mobile phone, even though a new mobile phone dedicated for gaming would be appreciated, for the ones who are interested, this is what the abstract states: An electronic apparatus includes a phone CPU and a game CPU. When a * key is operated during execution of a game, the phone CPU sets a specified bit of a game key register to "1".

The phone CPU is set "1" into the specified bit when there is an incoming call of a phone during the execution of the game. The game CPU pauses the game being in execution when the specified bit is renewed to "1" and restores the specified bit from "1" to "0". When the * key is operated in a state the game is interrupted, the phone CPU sets "1" into the specified bit. The game CPU restarts the game by canceling the pause.