It exists and has been revealed.
After much speculation, the MMO version of The Elder Scrolls role-playing series has officially been announced. Developed by ZeniMax Online Studios, The Elder Scrolls Online will allow players to quest across the entire continent of Tamriel 1000 years before the events of The Elder Scrolls V, which includes the provinces of Cyrodiil (where The Elder Scrolls IV was set) and Skyrim (setting of The Elder Scrolls V).
No screens or video have yet been released, but more information will be made available through Game Informer, as the reveal is part of their June 2012 cover story.
Not many specifics are available yet, but according to Game Informer you'll be able to play as one of three factions, take part in open-world player versus player combat in the province of Cyrodiil and vie for control of the throne of the Emperor.
The Elder Scrolls Online is currently scheduled to be released in 2013 for Mac and PC. Be sure to check out additional details in the Elder Scrolls Online Wiki.
Too bad I don't play MMOs, bespite being ahuge TES fan.