When "Maximum" Bob expressed interest in a "Four-door Corvette" we think he meant something like the G8 GXP. Just in case, here's some horrible examples of why they shouldn't build an actual four-door Corvette.
This images comes from TopSpeed and envisions a Corvette lengthened with four doors. Scary.
This is probably closer to what we're talking about because it's Zeta based, but it's still just a good chop of what would be an ugly car by GMI poster Monaro SS.
Not a render, the Savage Rivale Roadyacht is an actual four-door folding hard-top Corvette made by a customizer.
To quote GMI poster E-Haskell: "It's like a 4 door Corvette... it just shouldn't be." Amen.