I'm usually a skeptic, but I can see that static electricity in carpet, the same they builds up from walking on it and shocks you when you touch a light switch, could possibly have some effect. As far as vibrations, that I do not buy. These aren't guitar pickups, they are straight lengths of 12 gauge wire! But I agree with the most of contributors here, go cheap. I fail to see how big money could have any effect on cable supports. Glass and ceramic carry static electricity on the outside, so do many plastics, remember the plastic comb trick? And balloons making one's hair stand up? Wood sounds like the best option. Here's an idea! Buy telephone poles made for model railroads! That would look awesome!
PS - I wish there was a "Like", button on these comments!