A while back some company was offering an assortment of replacement boots made of silicone. They were blue and very supple. I measured the big and small diameters as well as the overall length of the boots on my old ZJ and used those dimensions to order some replacements.
They were touted as being impervious to cold weather.
Truth is all CV boots stand up just fine to the cold. I haven't seen them offered for awhile, but I haven't been looking.