in a few years, we will all be able to buy scaled down "bloom" boxes, which are fuel cells that can be run off natural gas, propany, methane, etc. This are grid tied as well, but they could have an option to separate from the grid interface and run with a local oscilator to supply the home during an outage. Your PV could then run off that as well..
http://www.engadget.com/2010/02/22/the-bloom-box-a-power-plant-for-the-home-video/