Whatever the device is, Iwata said it would also be a clue at the N5. If it's a VR device, that'd be to say the N5 would be (or have) a more advanced version of it.
If a VR system were to be Nintendo's MAIN platform, they would fail before they began. VR is niche no matter how cool it is.
I'm betting my first born (again) that it's not VR.