The latest issue of japanese gaming magazine "Game Labo" contains a rumour about a "Virtual Boy 2", which is under development not as a standalone system, but rather as a peripheral to the Wii. It's said to be released around the end of this year.
So, not really a "Virtual Boy 2" as they call it, but stereoscopic goggles for the Wii? Game Labo are known for their fishy rumours, but if there's any truth in this, we might learn more on Game Developer's Conference 2010, held in San Francisco from March 9th to 13th.