GTA creator, Dan Houser, basically confirms GTA for 2012/2013
 

In an interview for GTA III's 10th Anniversary, he was asked this

Are you looking to the next stage of the GTA franchise?
There is gonna be one? I don’t know. [Smiles] I know nothing about anything after Max Payne 3.

If you do a little bit of obvious reading between the lines, he's hinting at the game being either revealed or released after Max Payne 3 next spring! (Because I doubt he knows nothing about any games following MP3)

http://popwatch.ew.com/2011/10/21/gr...ry-dan-houser/