Great idea.
I like the idea very much. It is not a generator, but it will provide a good amount of power for a reasonable time (maybe an expert can tell us just how many KWhours are in the battery?). And it will be nice quiet power, unlike most home generators. Probably also very clean (electrically) power for computers and such.
Most of us have two or more cars, and the Leaf would probably be the only electric one so we could drive the other vehicle (or bike) until the power comes back on. Or we could charge the Leaf with the generator in the middle of the day, making nice quiet power at night.
The point about the transfer switch is well taken. In may places it is illegal to power a house without a transfer switch, something Nissan would have to address before offering this. But many people already have transfer switches installed.
This feature could convice me to buy a Leaf.