I have an idea that goes along with the Flynn Parallel Path or the Hilden-brand devices for a kind of magnetic on/off switch. I will throw it out in the open just in case someone else wants to give it a try. What Im thinking of is a metal pipe with caps on each end and an spacer in the middle making two sections. On one section is a magnet and the other a coil with an iron core. I am no good at explaining things so I have made a model in blender. I have also included some visimag images using the same concept. In order to get it to work correctly I had to add a fairly large air gap between the spacer and the coil core.