Milwaukee has some heated gear that is powered by the same battery that runs it's tools. Might be of some interest to those who don't like cords.

Heated Jackets
Durable carbon fiber heating elements: Distribute heat to core body area and pockets
3 heat settings: Adjustable by zone to provide the right amount of heat to the hands, core and upper back
Water/Wind Resistant: Internal storm flap and thermal knit fleece inner lining keep the weather out, and heat in
Versatile battery holder: Features a battery fuel gauge and built-in USB port to charge phones and other portable electronics

The ad I clicked on says battery life is about 6 hours. I would have to have an extra battery (or two) to use this type. My Gerbings have never failed me though. (Now where did I put that wood???)