A question I have had about hybrids is why they don't just use the electric motor as primary propulsion and the gas (Diesel) engine purely to recharge. This would do away with a transmission (potentially, you could use a two speed variant), the alternator, and provide the "instant" torque of the electric motor. The gas engine could be designed to run at some narrow RPM range for efficiency just to drive a generator.
You could have electric motors on each wheel if one wanted AWD and traction control.