forms of fuel are not a power source, they just keep the power source going. however if someone was to have one of those cars with an engine up front, and an engine in the boot, that could be different
To rank as a hybrid, you need to have two different types of power production. Two engines of the same type won't qualify. You would need petrol and one of the following alternatives:
electric
steam
nuclear (greenies would love that one)
rubber band (health freaks would love this - imagine the exercise winding it up)
mouse driven wheel (RSPCA might object to this one)
pedal (well, it IS alternative power, isn't it?)
Probably others I didn't think of at 5.30 in the morning......