I have proposed a simpler method to avoid bowing, although it requires some unusual timing for the crew.
The bow is the result of thermal convection within the case - warmer air rises to the top. If one were to "tickle" the starter for a few seconds, some xx minutes after shutdown, it would stir up the air and randomize the rotor positions, thus causing the bowing to be somewhat reversed. I haven't seen where anyone has tried this gimmick.