A transformer doesn't magically increase the wattage. It remains the same.
The point of going to higher voltages is essentially to increase the maximum wattage you can supply to the motor, while still using reasonable sizes of batteries and wires.
1,000 watts is 1,000 watts. 1,000 watts at 12 Volts is 83.3 amps, but 1,000 watts at 60 Volts is only 16.666 amps.
Higher volts and fewer amps will always result in more efficient power transmission.
Quote:
Originally Posted by Fab Man
maybe some day when EV's can achieve 200+ mile range I may build one myself.

They can, but the cost of the batteries to do so is still exorbitant.