I stumble over unserved markets all the time. For example, a lady stopped me while I was driving the Sparrow, and we spoke of its appropriate use as a vehicle for teen drivers. What do parents want?
Limited independence for their teen driver.
The Sparrow is perfect: having one seat eliminates the joyride factor, the horse-power limiting software eliminates burn-outs while allowing freeway speeds, and the limited range means you know your teen is within a half-hour radius (and will probably come home to charge the car).
Some car company should totally make a "training" car, that was safe but of restricted utility (perhaps with a 3 gallon gas tank and no room for making out).