I can't imagine that the Z06 and ZR1 would be going away for the C7. But, I agree that we won't see them for the 2014 model year. It only makes sense to work out the initial C7 kinks in the base model, before developing higher performance versions. And we'll have the Z51 for those that want a higher perfomance package in the 2014 base model.
So maybe 2015 for the Z06 and 2016 for the ZR1? I think the four current Corvette models (base, GS, Z06, ZR1) are a nice, profitable way for Chevy to sell Corvettes, and meet their customers' desires. So I suspect we'll see the all four versions for the C7.