To give credit to where its due, I got this from Greg McKenzie's webpage at
Try Dual-Star "Serious Trail and Motorcycle Adventure Outfitters" at http://www.dual-star.com/
They have a heated grip kit that says...
Mylar tape-style dual stage heating element (4" x 2 3/4") wraps around and adheres permanently to the handlebar beneath handgrips to provide toasty comfort at high or low temperature settings. Extra long 32" insulated wires are then routed along existing cables/looms. These tricky little items allow you to use the handgrip of your choice! 12-volt system draws only 36 watts.
In theory, you can then apply with any bar/grip combo available. I wonder how well they fit under a grip - how easy it is to install since the grips tend to slide on tight as it is without the mylar tape. Perhaps you have to get certain grips, but maybe Dual-Star can explain better.
Chiang Mai, Thailand