Soundwave on 02 January 2013
I could see a new console announced in 2-3 years, especially if Wii U flops in 2013 and beyond, but it probably won't even be a console, it'll be Nintendo washing their hands of the console market entirely and making like a tablet which has the option of wirelessly transmitting a signal to the TV (so the reverse of the Wii U in effect).
Then again, the successor to the SNES (N64) was announced in August 1993 (Project: Reality) when the SNES was barely 2 years old in the US.
And the GameCube (Project: Dolphin) was announced at the 1999 E3 show, when the N64 was just 2 1/2 years old.
