I don't think the USA is ready for a turbo ZR1 just yet. The Corvette is too much of an icon to choose something associated with ricers/JDM/Euro cars instead of the American-as-apple-pie supercharger.
Considering the number of Buick's currently being built with turbo engines, I don't think idea of a twin turbo Vette that far fetched at all. I believe GM went with the supercharger over a turbo setup for the LS9 because of packaging and cost, with the blower everything is relatively cheap and totally self contained, which has allowed it to be placed into quite a few different cars with minimal modification. With a turbo setup they'd have to deal with mounting, running the piping, intercoolers, ect ect for each car instead of just dropping it in like in the Camaro and CTS-V.
Odds are GM will just bolt the current (or a slightly revised version) Eaton onto the LT1 and turn up the wick a bit to around 650hp. But then what happens with the Z06? Unless GM has a 500+ NA version waiting in the wings (which is very possible, but I doubt it would be 7.0l like the LS7 was), I don't know what they could do to make all three versions of the car significantly different from each other.
P.S. I still hate that they're calling the new engine an LT1, they should have just stuck with LS.