Looking at the possibility of such a title
Polyphony is looking at the possibility of a PlayStation Vita version of Gran Turismo. While nothing is set in stone yet, the developer is looking to extend the Gran Turismo title on to the portable unit and take advantage of the innovations offered by the unit, including the possibility of 3G support.
In the meantime, Polyphony is already working on the next Gran Turismo, which will be the 6th entry in the franchise. The developer has stated that a potential framework for the game is being worked on, with the goal of making it the “state of the art” in a racing title that will feature the latest in technology and expression.
No word from Polyphony if GT6 will be a PlayStation 3 or PlayStation 4 title, but whispers that we hear suggest that it is likely that the framework that is being put down for the GT6 will be for the PlayStation 4 in view of how long it took to get the last version done for the PlayStation 3.
Gran Turismo 5 has some work to do to catch up with Xbox 360 competitor Forza Motorsport. Forza 4 added a number of new features and concepts to a racing title that will put the pressure on Gran Turismo to match in its next release.
In the meantime, Forza will see its franchise expand later this year with the release of Forza Horizon, which will increase the pressure of developer Polyphony Digital to consider expanding the Gran Turismo umbrella to consider another title that would join the Gran Turismo franchise. Sources suggest that the developer is considering its options in this regard.