Im building a generator soon that uses magnetic repulsion based on this design:
http://www.youtube.com/watch?v=Ooa8EBXKDW4 . Its pretty cheap. I ordered 50 high powered disc magnets for $90 and im either going to use wood or plastic moulds for the magnetic wheels (this will be the tough part). Im gonna get a standard petrol powered generator (probably for 20$ at a scrap yard) and remove the combustion engine and replace it with this magnetic motor. Attach the magnetic motor to the existing dynamo built into the generator. The cog sizes will need to be adjusted for the correct RPM into the dynamo. It should have sufficient power for a small house or else just dont use a lot of electronics if your in a big house. Make a lead with a plug at either end and if the main power should go out plug this lead in to the generator and then into one of the wall sockets of your home. I havent tested this yet by the way. Its still just an idea. Im waiting on parts to arrive at the mo and ill post results and videos when/IF complete.
Peace&Love
TV2012