If there ever is a V6 in a Vette, it's going to come because of Government regulation, that is: the car will get a V6 turbo because that's the only way a Corvette could still offer some sporting performance and meet Federal regulations for exhaust emissions, particularly CO2, and fuel economy.
But...in the near future, my guess is that Corvette out through 2013 or 14 are going to have V8s. Now, it's unlikely they'll be 505-hp 427s or 638-hp supercharged six-twos--that stuff goes away at the end of next year--but you might see a 4.8L or 5.3L supercharged engine as an option or maybe even standard.
The "C7"?
Well...rumors for a while were that this was to be a mid-engined and lighter car. But, what I've heard lately is the mid-engine idea has been discarded as too costly considering 1) GM's financial situation and 2) that performance cars may become "politically unfashionable" as products made by a company which has become a Government-funded jobs program for the UAW.
I don't think the Corvette is going away anytime soon because of it's value as halo brand and that it's an American icon, but I think it will be a fair amount of time before we see a "C7" of a dramatically different design as was the C4 compared to C3.
It's always fun to speculate...
How 'bout, for the 2016 Corvette, a chassis configuration like something that Mosler or Factory Five makes, styled like a Corvette should look and with a series hybrid powertrain using a small, gas turbine (ie: a jet engine) running on diesel fuel to charge the batteries?