Source: http://www.made2game.com/
Bethedsa has all but confirmed that Elder Scrolls V is in production according to Eurogamer Denmark.

It was confirmed from the sites source (who had the official game documents in hand), the game is definitely in production and will be a direct sequel to The Elder Scrolls: Oblivion, which in our opinion is one of the finest RPG’s to date.

Unfortunately due to an NDA the site was unable to disclose any further details, however it looks like we may be hearing more about this sooner rather than later.