@Scrawnton Eh... I think you're wrong. The Wii version of Tri sold like a half a million copies here and nearly a million in "the West", and this is considering that the series has always been way more popular on handhelds. A 3DS exclusive 4 could potentially sell a million in NA alone. I doubt they will ignore that.
Plus Nintendo themselves seemed to heavily push to get Tri released in the West. There could be some partnership.
I don't know if Tri ever broke a million in the States, but last I recall it topped out at over 900k, which is nothing to sneeze at. I'm looking forward to a localization, because Capcom would be retarded not to bring it over.