Hypothetically speaking, if you were to produce a 2.5 tonne car what drive train configuration would suit it best? My initial thought would be a 4x4 set up as this is most common in heavier vehicles.
Furthermore if we say the vehicle in question is electrically driven, with one motor at the rear. The vehicle is capable of high torque and power.
Would this be a good idea, or is it a recipe for disaster and how would the car behave on the road?
Why do you think 4x4 is most common? may be more prevalent now, but go back prior to the introduction of the Mini and just about every car was rear wheel drive.
If you look at the large cars, then it is only fairly recently that they have started doing 4x4 versions and some of the quality manufacturers have only recently produced a 4x4 variant, think of Rolls Royce... In terms of the number of years they have been producing cars then 4x4 is very new...
In terms of handling, rear wheel drive is not a problem, why do you think F1 cars are rear wheel drive? The use of fwd is to maximize the available space for the occupants...
The "electrically driven" is an important point in this determination. AWD in electric vehicles is generally done with one motor on each axle, and the big disadvantage of RWD/AWD in ICE-powered vehicles - the presence of the transmission tunnel housing the gearbox between the front footwells, and the propshaft running the length of the floorpan, then goes away. This was the main reason that FWD became popular, the engine and transmission was a combined unit attached to the front end of the passenger cell, which was then a box without the intrusions for the drivetrain that then restricted the layout, so smaller cars could have good space inside.
For any car, the majority of braking effort is done on the front wheels, so for an EV this would indicate that for good regenerative braking, a motor would be needed at the front, otherwise the mechanical front brakes would be dissipating most of the energy and the rear motor would not generate much. For a high performance car, a rear motor makes sense to get good traction on acceleration, making the AWD setup a logical choice, but a heavy, but not high performance car could well get away with a front motor only.
