I have thought of using heatshrink tubing or other coverings as a shield around some plain-old PVC insulated shielded wire, but I have to imagine theirs somewhere to get the right stuff. From the shape of the wire on my 1984, which has never seen a winter, there has to have been improvements to a solvent/heat resistant shielded cable. If I can't find anything, I will probably use heatshrink tube and maybe some plastic split cable shielding also.