How about regular electric wire. You could strip the insulation off (or get non-insulated copper wire). It is braided fairly tight and being copper could be bent and flex easily. You would have to paint it, but that shouldn't be much of a problem. You could probably find it ina small gauge with a high strand count as well, which would probably look more like real cable rather than the 2-3 strands that are in the picture hanging cables.