Material with low k-value that can be used for high-heat rods?

giant016

I am modifying a vertical hotplate that has two heating elements that clamp together. This is done by a jack screw and some rods that slide. The jack screw I'm not concerned about, but I'm looking for something that can resist heat better than the stainless steel rods we currently use. The sides of the hotplate currently get hotter than I'd like as it would be nice to be able to turn the hotplate over to use it as a horizontal as well, without having to remove the part.

I'm looking into zirconia, but do you guys have any better ideas? I'm getting quoted on the zirconia (guessing it's pricey), but if we could keep the cost below $50 a foot that would be nice. For reference we'd need it to be about a 1/4". Thanks for any input.