Rumor: GTA5 out before next Holiday.

[Fumanchu]

In a similar vein to the 'Vice City' spin-off it could very much be achieved. So much of the game is recycable to a new 'edition'. From art assets to animation cycles to NPC AI - the ground work has been done essentially. This game would probably cost 10 million to make instead of GTAIV's 100million.