I had an idea for tractor beams for purposes of towing. It would require code changes however. You simply use a floating dockpoints... that is dockpoints that sit some distance away from the hull. You may be able to get away with making one only for the vessel doing the towing, and use one of the existing dockpoints on the vessel being towed. The part needing code changes is a beam-fire-continuous sexp, which would have an argument to disable or enable the effect with the same sexp. Then you make a beam with the tractor-beam effect (visual), no damage, no mass, and no impact effect. Then make sure that the beam widens, combine the right sound effects, and you've got your tractor beam.
