I'm 99.99% sure there will be. And according to Aounuma, the 3D is going to "mean something." I've heard people say he was talking about MM3D in that interview, but that doesn't make sense because the question specifically said other than the rumored Majora's Mask were there plans for an original Zelda on 3DS. A new game is probably already in some stage of it's development, even if it's just the earliest planning stage. It could be several years before it's out, but I'm sure there will be a new 3DS Zelda.