"Sport Truck," or ST, is just a placeholder. It's the generic name for the El Camino-style 2010 Pontiac G8 variant based off the Holden Ute. Try saying "Ute" over here without sounding like Joe Pesci describing a young person in "My Cousin Vinny." GM is holding an online contest at www.pontiac.com/namethiscar to pick a name. The result will be announced on April 15.
It could've been Caballero, after the late-1960s/early-1970s GMC version of the Chevy El Camino. GM is "tripling" its Buick-Pontiac-GMC dealerships in the States, and all you'd need is a different nose for this thing. It wasn't the cost of a new nose that made GM pick Pontiac over GMC. It was, to quote product manager Brian Shipman, because of the Ute's sportiness, and "it probably wasn't the best fit for 'Professional Grade.'" The two-door, he says, is a better fit for Pontiac.