However, I'd much rather take the scenic route via 101 and stop over in Paso Robles and get the car charged up while at a nice B&B, wine tasting, etc. ;)
That being said, the 'long trip' scenario is somewhat of red herring. If you regularly travel several hundred miles a day then an all electric car is probably unlikely to meet your vehicle requirements. If its an occasional (once a year) kind of thing then creative solutions might arise to address it.
Were the Tesla guys willing to put a high power plug in the back I could imagine a 'trailer' which held a generator and a gas tank and provided power all the way there.
As someone with a family, my requirements for a family car need to cover the possibility of extended road trips. Sure, I know that in theory I could just rent a gas car for that, but I know in practice that it won't happen. So "able to handle long road trips" is solidly in my personal list of firm requirements for a family vehicle. Sure, I don't need to do it every day. But it is something I need that vehicle to do.
And I agree, SF<->LA is not a long drive.