I don't have a dog in this hunt but I do own a couple of Prius (Prii?), and '02 and an '07, and I'll agree hybrid engines are a constantly moving target, they are up to Gen III or Gen IV in the latest models. The 02 or 07 could be used as a pretty good generator substitute up to the practical limits that electricians can factor out for you - the gas engine would run only to top up the hybrid battery to continue putting out the current necessary for whatever load you're putting on it. Provided the load is low enough that it doesn't do long term damage to the hybrid battery then this might be worthwhile; watch out though for loads that could drain the battery to zero and cause a warranty repair, which nowadays runs about $3-4K for a Gen I battery (02 Prius). Frankly there is a lot of instrumentation to prevent that in driving scenarios, but they still advise you not to drive with no fuel.

Not sure where folks get the $10K cost differential between any Prius and an equivalent make/model, AFAIK the base Prius 2012 Gen III/IV runs $18K and has the most efficient mileage and hybrid battery to date, excellent durability and costs of operations etc; maybe if you buy an $8K Kia this could pencil out better to buy the Kia and the generator, however for the 99% of the time you're driving the Prius you are not, to put it bluntly, driving a Kia. I know, I've driven both, and a Prius is not a Kia like a Lexus is not a Yugo. But I digress...

On the more modern 2012 Prius there is a noticeable difference in gas mileage and battery operation over the 07, you cruise along below 28 MPH and you do so on electricity, no gas used. If you are waiting in a NJ gas line for hours this would be a great advantage over a conventional gas engine which has to run to give you heat; the Prius just used electricity and only powers up the gas engine to recharge the hybrid battery. Based on car rentals where I drove modern Prius I've gotten 50+ MPG and can attest to this stealth mode of driving electric.

My brother has a Chevy Volt and it runs fine on electricity for relatively short distances (commuter range). It needs to be recharged, and if electricity is out at your house you're up the creek - without a generator. In comparison the hybrid (gas-electric) has some definite advantages.

All this said the Prius has about a 300-350 mile range on a full tank and I factor that into our bug out plans; more modern Prius have larger range of travel on a single tank. And on the whole the Prius like many other cars does a good job of recharging from the 9V outlet and can handle the majority of comms and computing devices. During one windstorm I also recharged a small generator intended for running lights etc from the Prius during the day to allow hours of lights at night.