The BMWi3 has an innovative mile extender - a small gas engine that recharges the battery as you go. It would be a good idea to include this as an option for those taking long trips. It could be manually started as you begin a long trip when the battery has depleted 10% and it should be able to extend the range by at least 50%. Again it would be activated manually for long trips.
I know it impugns the ideal of pure electric use, but the bottom line it would be a practical OPTION.