GM is considering adding more variants of the Chevy SS to the US market if there is enough demand for the sports sedan. The Chevy SS would have to meet its target of selling 2,000-3,000 units per year in order for GM to go ahead with the production of SS variants.
No word on what these extra SS models would be, but the Holden Commodore on which it is based is available in 455 and 580 horsepower variants with both manual and automatic transmissions. The Commodore also comes in a number of body styles, including a sport wagon and an "ute" pickup truck.
If GM decides to go ahead with more SS variants, they will likely arrive on our shores no later than 2015.