It's so easy to rotate an engine on a normal engine stand, why go to the hassles of all that extra work to make one that rotates unless you making a display motor for looks only and if for rebuilding would have to incorporate a locking pin to stop it rotating when doing things and if you add a motor to have it turn at a slow speed, seems to me you are overthinking things, have too much time on your hands that you are bored, no I just use a normal easy built engine stand that only gets used once in a while and its only used to pull the head and barrels off and back on and timing cover but have to be removed from the stand to split the cases.
But I like the idea of the rotating Xmas light display, anyone got a spare motor they can give me, I take it off your hands, no I think I got better things to do.
Ashley