According to Nintendo President Satoru Iwata, the company has recently canceled a completed handheld system in the last three years.
From the article:
"It seems that Nintendo had completed development on a new handheld system sometime in the last three years, but canceled it before revealing it to the public. Iwata would not elaborate on whether it was another refresh of the DS (which has been upgraded twice, first as the DS Lite and more recently as the DSi) or if it was the fabled 'Game Boy Evolution.'"
Iwata also used the interview to reiterate that Nintendo does not plan to drop the price of the Wii anytime soon.