Soundwave on 25 December 2013
I think the next Nintendo portable will be a new third pillar product line.
Something more akin to a Nintendo tablet which has the horsepower to even approximate Wii U engines/ports at lower resolution/assets if Nintendo wants to dual release some games.
By late 2015 this should be comfortably possible for Nintendo at an affordable price.
I say that too because it seems like the 3DS seems to have had its peak year in Japan hardware wise, even with MH4/Pokemon sales are going be more than 500k short of last year there. In NA/Europe this fall is probably the 3DS peak. So I don't think Nintendo will just accept lower 3DS sales every year from here on out.
