While I didn't get to talk to Audi's Head of Development at the Geneva Motor Show, others including CarAdvise did and according to Hackenberg, a breakthrough in battery technologies put the R8 e-tron back on track:
I was looking at the reasons why the R8 e-tron was cancelled, and one was the range – about only 140-150 miles. Now with the team we found the possibility to go beyond that, between 250 and 300 miles.
We are thinking maybe to release the R8 e-tron as a production car. I personally need such a car as a technology vehicle to bring in new technologies, step by step – every half year or every year there will be something new.
At Volkswagen (where I was development chief) I used the XL1 as such a car. For Audi, the R8 e-tron would be good car for doing such things, so I am fighting for that.
The production decision would be made shortly, and the expectation is the Audi board will give it the green light. If everything goes as Hackenberg planned, expect a very fast zero emission ride indeed using a carbon-aluminum hybrid chassis and enough torque to move a mountain.