Yes I am using e3d hotends, v6 (0.4mm nozzles and smaller) and volcano (nozzle larger than 0.4mm.
Having a own smart effector for every nozzle might be a little overkill, not to mention that it would be a little expensive. The ultimaker-printcore way would be perfect, but I am afraid I would have to design it myself for the smart effector. Probably it might become a little bulky.
But the option with the pigtail connector seems quite nice. I will give it a try.