I've got some LG neoprene shoe covers that I'm happy with. They go over my MTB lugs just fine covering the entire toe region and having a wide strap across the underside of the arch. The cleat area and heel tread are exposed. From the sole up to lower calf is completely covered in neoprene with a good, air tight velcro closure on the side. They even work with my light hiking shoes. Over a good shoe with a heavy wool sock I'm good to somewhere below freezing for 30+ mile rides. When it finally gets too cold for the shoe covers, I switch to insulated, water/windproof winter hiking boots and ride the flat side of my pedals. I don't do a lot of sprints or hill climbs at around zero F so it doesn't bother me not to be clipped in.