Electric car vendors: bundle in short-term gasoline car rentals, with charging
Looking at new electric cars like the Nissan Leaf, we see that to keep costs down, cars with a range of 100 miles are on offer. For certain city cars, particularly in 2-car families, this should be just fine. In my particular situation, being just under 50 miles from San Francisco, this won't work. It's much too close to the edge, and trips there would require a full charge, and visits to other stops during the trip or finding parking with charging. Other people are resisting the electrics for lesser reasons, since if you ever do exceed the range it's probably an 8 hour wait.
An alternative is a serial hybrid like the Chevy Volt. This has 40 miles range but a gasoline generator to provide the rest of the range and no "range anxiety." Good, but more expensive and harder to maintain because electric cars are much simpler than gasoline cars.
Here's an alternative: The electric car vendor should cut a deal with car rental services like ZipCar and Hertz. If you're ever on a round trip where there is range anxiety, tell the car. It will use its computer and internal data connection to locate a suitable rental location that is along your route and has a car for you. It will make all appropriate reservations. Upon arrival, your electric car would transmit a signal to the rental car so that it flashes its lights to guide you and unlocks its doors for you. (The hourly car rental companies all have systems already where a transmitter unlocks the car for you.)
In many cases you would then pause, pull the rental out of its spot and put your electric in that spot. With more advanced robocar technologies, the rental would actually pull out of its spot for you. Zipcar has reserved spots for its vehicles and normally it makes no sense for the renter to have just pulled up in a car and need the spot, but it should work just fine. At Hertz or similar companies another open spot may be available.
Then off you go in your gasoline car. To make things as easy as possible, the negotiated contract should include refill of gasoline at a fair market price rather than the insane inflated price that car rental houses charge. Later come back and swap again. Ideally, some basic number of these quick rentals would be included in the price of your electric car. That way, if you only use it occasionally you will suffer no range anxiety -- not even anxiety about the extra cost of the rental. Multi-day rentals and highly frequent rentals would require a cost -- this is not something you can give for free to a commuter doing it every day.
On top of all this, the contracted rental companies would put charging stations in their spots, so that you can charge your electric car while you have the gasoline one. This would mean a serious increase in effective round trip range with minimal delay. Of course, the rental companies could have electrics of their own, and use these charging stations for those. There is no reason you could not be swapping your empty electric for a fully charged rental electric either -- a different way to do a roundtrip-only form of "battery swap." For example, I could drive 35 miles to the SFO rental car center in a 100 mile range car, grab another 100 mile range car for an active day of driving around San Francisco, and come back to swap even if there was no charging station in the parking space. But even somebody 95 miles from SFO could do this if there were a charging station.
This can't do everything. It doesn't readily permit circle trips that don't come back the way they came. That's pretty common for me, with two highways to choose going to SF, chosen based on traffic, and 5 nearly equivalent routes to Oakland. The vehicle swap will start out less seamless and improve, but of course the big thing is finding a rental that is on your route.
This can be made cheap if you don't absolutely guarantee it to be free or cheap. Ie. it could come from unused inventory of the rental car companies, who will sell that for less. When inventory is tight, they will want to charge a bunch more.