Where Were You When the Lights Went Out?
If you were with your car*, and weren't at home, so much for all your scheming...
Of course, the home UPS part of this project is critically dependent on the car actually being home when there's a power failure. The power grid issue isn't - they don't care about your personal installation, they care about statistics, and when you're out your neighbor may not be. Even so, no car, no power for the fridge.
You can get a second hybrid vehicle. The choices are increasing by the day. Once you set up your system, the cost of incorporating a second vehicle is minimal - another docking adaptor, a big relay, and some control circuitry. If both vehicles are the same model you can just park whichever one is home in the dock. (If both are out at the same time, maybe nobody is home and you won't even miss the power!)
Do some general planning. You probably already have UPS units for your computers. If you bought these a number of years ago, you may not be aware that the prices have come down drastically, and your batteries are no good any more. Get some new ones for your computers and use the old ones for little things like electric clocks and gadgets that are nuisance to reset but take almost no power. The new ones for your computers have the additional advantage of being able to commune with them and tell them to shut down when the UPS batteries are depleted.
Plan for special requirements. Medicine that must be refrigerated? If so, you can get a small refrigerator just for it (and, of course, for your emergency ice cream supply) and get a UPS just for it.
Remember short power outages are more an inconvenience than a problem, and not even an inconvenience if your computers and other gadgets have their own UPS. Longer power outages can be a big problem, but in the typical case, you or your spouse in the other hybrid is likely to return within a few hours.
My own solution is that I have put a (refundable) deposit and a Toyota Highlander Hybrid to replace my aging Audi. Even though it's an evil SUV, it's not as evil as most, and should get significantly better mileage than the Audi it will replace. My conscience suffers only minimal twinges. The dealer (as of May 2005) refuses to speculate as to when I will receive it. And I'm definitely holding out for blue this time.
Followup: I declined delivery of the Highlander. I read an article in which Dave Hermance, the Toyota factory Hybrid Guru confirmed that the Highlander Hybrid would provide only 1mpg better mileage than the standard Highlander. I read a subsequent article that claimed that Toyota is planning to add a switch that will allow the driver to select "power" or "economy." I've told the dealer that I will reinstate my order when that eventuates.
*At least it can furnish an alibi.
Updated 28 June 2006