One thing: Virtual Boy was not VR, it was just a screen inside a headset, it did not detect movement (nintendo's product is supposed to be for detecting movement). VB was too heavy, too expensive, and only one color, basicallly ahead of it's time for portable consoles, and in a bad way. We're on the brink of virtual reality headsets, it's only a number of years until they're common.
Now another thing is: people are speculating on here that the mystery product is a device that can play gba or gc games, or a portable dvd player, etc, the fact is the new device is not something that does what gba and gc does, but rather complements them, nintendo is not going to release something that can do what gc and gba do alone.