The game, according to various places like Kotaku, takes place in LA (or the GTA version) and is said to include multiple main characters. The logo reads Grand Theft Auto V Five. What if the logo has V and the word five because we'll have five main characters to control.
Either we'll have the choice of one of five characters like the original GTA or it'll switch from person to person. Mr A will be our guy for a chunk, then Miss B will take over for a while before we get to play as Mr C etc.
They could have them all be members of one gang trying to take over the city/state or seemingly unconnected people who happen to have interweaving stories.