A Rockstar Games online title featuring one gigantic city rampant with endless shootouts, carjacks, and fist fights on every corner – in other words, an MMO variation of Grand Theft Auto, which Sam Houser, founder of Rockstar Games, perceives as “the Holy Grail.”
Speaking to EGM, Houser commented that a GTA MMO "is very, very doable and is a very, very compelling proposition". Despite this, however, he also pointed out that a title of this scope would ultimately lack any relevance, other than to place thousands of players into one city with no purpose other than to just endlessly shoot each other.
So it would appear that no such project is being worked on at Rockstar; however, that does necessarily mean that the company may not seek out ideas and concepts which could allow a GTA MMO to be more persistent and relevant.
Grand Theft Auto IV, Rockstar’s latest project will feature online multiplayer, a first for the series. Details regarding this feature are largely unknown at this point, although more information is expected shortly.