http://www.ebay.com/itm/Universal-M...ash=item20f9cab1fb:g:2DwAAOSweW5VI1O0&vxp=mtr
Rode with them today for about 1/2hr. Weather: slight breeze 6-8mph, 50*F and sunny. I wore my leather, non-insulated summer gloves. Speeds up to 60mph.
Verdict. Not as warm as those mitts, but they do block some wind off your hands. My hands were only a little chilly; without them they would have been pretty cold. It would have been perfect with heated grips and/or insulated winter gloves. They block the bottom half of the stock RS mirror, a bit more than I'd like, alleviated by sitting a bit more upright. Had to tighten down the expander bolts more than I'd like, but that was because I didn't get around to finding suitable rubber donuts; but the guards did not rotate.
For <$30 it's a cheap experiment.