German automaker Smart is gearing up to launch its next-generation ForTwo city car. A prototype was spotted being tested and a stretched four-seater version is also in the works.The major limitation of the minuscule city car has been its inability to carry an extra passenger or two, though this could change by 2013. IMAGE GALLERYWhile the standard Smart would remain a pure two-seater, a new Smart ForTwo+2 will seat four and feature as many doors. This will allow better access into the tiny rear. An additional model would make the Smart range more competitive with base-level city cars such as the Chevy Spark and more premium vehicles such as Audi's A1. It will be Smart's first four-seater since the failed Smart ForFour.Each model will remain rear-wheel-drive, keeping the engine below the car's floor. Rumour has it the new model will have several engine options, including a hybrid and an an electric motor.