Probalbly would make my beach bars difficult to handle in tight situations, but it would be like trailer mirrors on a truck as far as visibility rearward.
My guess is on a sport bike it wouldnt look to bad due to the short length. But on a bike with a wider span.. it would accentuate the width. making it look like wings. And manuverability on my RK is difficult now. I wouldnt want to make it worse. Good idea though. Someones gears where turning.