There are some 100 psi kevlar beaded Ritchey slicks I've been using for years, but can't seem to find anymore (the now-defunct bike store at Dupont Circle must have bought a whole warehouse of them when they went out of production). They would last forever in warm weather, but the sidewalls would start to crack in severe cold (<15F). I don't think the mercury has gone below 25 this winter, so they would have been fine.
