It was back at the 2009 Frankfurt Auto Show where Audi
's R8 e-tron supercar concept made its original debut. Since then, the automaker has continued development work of the all-electrical supercar, but we still have yet to see a production version after three years. So what gives? According to a new report coming from Car and Driver magazine, all advanced work and testing on the R8 e-tron program has been halted, largely due to the rising cost of batteries.