flyme237: Can you explain why the 'towbar' is not suitable for towing the aircraft? Could it be made more suitable via a modification?
For cold starts I'm not sure that turning the prop will reduce starter load appreciably, unless we're talking about a radial or inverted engine where hydraulic lock will overcome the starters efforts, and possibly damage the engine. It's probably not worth doing on a flat four/six cylinder engine.
On engines where magnetos provide the sole source of the spark, the battery is not part of the ignition system, so providing there is fuel in the supply to the engine, the engine would still run for long enough to do you a serious injury.
take care
tp