You're not likely to see a Nintendo phone any time soon, but the company did look into making one almost a decade ago.
Over the past few years, one rumor that's continuously reappeared on the Web has been that Nintendo's working on a mobile phone that would double as a handheld console. As of right now, this isn't the case, but Pocket Gamer has learned that the company was considering such a project during the early 2000s:
"A development source, who preferred to remain anonymous, has revealed that there was a skunkworks R&D project run by Nokia and Nintendo in the early 2000s - about the same time Nokia was working on its original N-Gage phone.
"The R&D efforts, which were located at Nintendo's Japanese HQ, were successful enough that the concept of a Nintendo phone was taken to the company's board of directors for approval. It was rejected.
"At the time, Nintendo was starting work on what became the DS, and presumably thought a dedicated portable console made more sense."
In all honesty, Nintendo's decision to reject the phone idea (even ignoring the decision to instead pursue the DS) was probably for the best. Nintendo was working with Nokia at the same time as the N-Gage was being developed, which was both a spectacular sales failure and a pretty rotten gaming platform. Meanwhile, the DS has gone on to sell over 100 million units, so I'd say that Nintendo's board of directors made a good judgment call.