re: are there hard numbers on the pollution benifits of electric cars?
Do they reduce pollution, or do they simply change where the pollution occurs? (power plant vs exhaust pipe) -- Yes, if clean power sources such as wind, photovoltaic and sea thermal power are used. Partially, if coal plants are used, since large power plants are more efficient than small car engines.
If we went to all electric cars could our power infrastructure support it? -- Not at present. Car energy use is roughly equal to electric power usage. So we would need to roughly double our electric power generation to make it work. It will take about 20 years to do this.