According to the latest print edition of Motor Trend Magazine:
"The rollout for the C7 Chevrolet Corvette will look like this: The standard coupe will launch in late 2013 or early '14, with the convertible coming three to six months later. The Z06 is next, a full year after the standard coupe. Then comes Gran (sic) Sport coupe and convertible, with the ZR1 the last of the next-gen Corvettes to hit showrooms. Rumor has it that the ZR1's supercharged 6.2-liter V-8 will shrink in displacement slightly, for corporate average fuel economy reasons, and there will be a 3.6-liter V-6 version of the base Corvette, though not at launch."

Below is Motor Trend's prediction:

Fourth Quarter 2013 / First Quarter 2014 - Base 2014 Corvette Coupe
Second Quarter 2014 - Base 2014 Corvette Convertible
2015 Model Year - Z06 Coupe
Later in 2015 Model Year - Grand Sport Coupe & Convertible
2016 Model Year - ZR1 Coupe