I am still hoping we might be able to construct our own cells at some point with enough capacity and other good charactaristics. Commercial 400-500 lb battery units will probably be far too expensive.
China could do it now for the right price and probably are. The string of middlemen and controlling issues will probably make those batteries either too expensive or impossible to obtain for the individual.
We are on the threshhold of really usable battery types for electric cars in the near future I believe.