Mike, you probably already know this, but a lot of body heat is lost by handling the metal tripod legs. I have mine wrapped in that insulation that plumbers use on pipes to prevent heat loss. Take your tripod to the hardware store, measure a section of the insulation and diameter and slit it lengthwise and it slips right over the tripod leg (upper section only). It also makes carrying the tripod over your shoulder much more comfortable.
Being a Maritimer myself, here's a 'downhome' solution for you -- two hot hard boiled eggs wrapped in foil, one in each pocket. By the time they have cooled down, you have a snack for the walk back.
Great ideas Patricia!
Thanks to one and all for some wonderful solutions. Think I will combine a few to solve the "popsicle paws" syndrome. A friend of mine works for N.B Hydro and will get me a pair of insulated linesman,s mitts (go 1/2 way to the elbow).I shall make sure they are XL so I can fit a pair of thinsulate gloves inside. Have emailed two companies who make reusable chemical pocket heating sacs.
I use a pair of charcoal based pocket warmers, basically these are a metal case in which you place a lit/glowing piece of charcoal. They last about 4 hours, much longer than the chemical ones. I bought mine from a fishing tackle shop many years ago when I was prone to standing on very cold hill tops flying model aeroplanes.