I know, this is related to other posts but it is different too.
Many hiking books, such as Don Ladigin's "Lighten Up!" recommend using a lightweight nylon shell overmitt.
I generally use Black Lightweight Patagonia Capilene glove liners. I find that they keep my hands plenty warm when I'm active down to the 20s or even 10s F. The advantage is I can easily use my camera, GPS, etc. without the glove getting in the way.
A very lightweight nylon shell overmitt for when it starts snowing, wind blowing, etc. seems like a good method to keep my hands warm. (I know, I can't use the camera but under these conditions I probably would use it less or little anyway.)
I have never found any source for a nylon overmitt shell. Has anyone ever bought these, have them, had experience with this method, or made their own?