Install it on the underside of the electronics box - mirrors are adjustable for angle. Shim if you have to.
Check out CIPA's website - they're probably the biggest player (overall, anyways) in this market.
Look at ski/wakeboard boats - they have options for mirros that clamp onto tubing.
Google is your friend - I found these in about 30 seconds. Not sure if they would work for YOUR situation, though - it's hard to know without pictures!
Universally fits for 2" or 2 1/4" or 2 3/8" boat towers. you can make the mirror fits for more round wakeboard towers. Curved Mirror arm mounts to the wakeboard tower, not the windshield. Adjusted into any position for the max vision.
www.ebay.com
Shop for can-am Maverick X3 rear view mirrors, true HD X3 Rear View Mirrors glass lenses provide you with distortion-free and ultra-sharp images.
www.kemimoto.com