Diesel is still popular in Europe, and even a mild hybrid one could do well there. We likely won't see it in North America, but we might get 48 volt gas hybrids for several manufacturers. If the price vs. benefits are balanced right, a mild hybrid system could do more to increase the countries over all fuel economy than a full hybrid.
With what? Kia already has a full hybrid in the Optima and the Soul EV. Just the higher CAFE targets?