Which type of DC electric motor is the best suited for driving a mechanical clock?
The challenge is to get two or three separate hands moving from a single fixed rpm motor using only gears.
DC supply.

A stepper motor typically gives you 200 steps per revolution. You could gear that to give the second hand a step per second or half-second. You can precisely control it by microcontroller (so you'll have an accurate clock) and you still have all the gearing to play with between the second, minute and hour hands.
The stepper won't be cheating. It will be a sensible solution to the problem.