UPDATE: Here's Iwata's quote on the NX, translated officially by Nintendo:
As proof that Nintendo maintains strong enthusiasm for the dedicated game system business, let me confirm that Nintendo is currently developing a dedicated game platform with a brand-new concept under the development codename "NX". It is too early to elaborate on the details of this project, but we hope to share more information with you next year.
Also, Iwata said Nintendo's new membership service would play a key role in NX.
Nintendo, together with DeNA, will jointly develop a new membership service which encompasses the existing Nintendo 3DS and Wii U systems, the new hardware system with a brand-new concept, NX, and smart devices and PCs, and Nintendo will be the primary party to operate this new membership service.
Unlike the Club Nintendo membership service that Nintendo has been operating, the new membership service will include multiple devices and create a connection between Nintendo and each individual consumer regardless of the device the consumer uses. This membership will form one of the core elements of the new Nintendo platform that I just mentioned.