I looked at the bar end mirror options but they protrude out further than the bar ends and are half the mirror real estate of the stock mirrors. I split lanes in Los Angeles traffic with inches to spare at the widest, which are my bar ends. I can't have mods outside of my bar ends.
The cost of the mod is $6 for the clamps, I just replaced the back ends of the factory clamps and of course what ever mirror you wish, this particular model is $17 from EMGO which are as big as the stock mirrors. I just used block-off plates $9 to cover the holes.
All from fleebay.