Last February I got my hands on these Handlebar Booties courtesy of my buddy Andrew at Cycle Solutions. He let me know of these winter lovelies that are a wicked solution to the problem of winter riding.
Since I have been out here I have had to make do with various combinations of bulky gloves. And since I tend to run warm things get sweaty in some of the other systems I have tried. Plus the problem other issue with bulky winter gloves is that one start to lose feel, meaning you not only have a harder time gripping the bar but also as the glove thickness increases you start to lose that feel of what the bike is doing.
Similar to what you see riders use in Iditabike, but without all the extras like pockets. Enough room though if you want to stick a small camera for short periods.
The day these pictures where taken was -24 on the way to work and I wore just a standard pair of full fingers and no issue. Which for me is a good thing as Goretex gloves turn into a sweat sauna when I use them.
These are only usable on bikes with flat or riser bars. So that means road and cross bikes are out of luck. But this is about keeping the mountain biking in the fun of minus 20 Ontario winter.