I've thought about doing this myself.... Our fenders aren't stamped steel, so that kinda limits the location possibilities. I'd like to place mine in the exact spot where the 2 side reflectors are located. but there isn't any internal support for the blinker bolts at that location. I'm thinking about making my own bracket to attach to the internal support under the fender and then drilling a hole for the blinker bold in the same place as the reflector. I haven't taken the time to get measurements and stuff, but it shouldn't be any harder than making my own Side mount plate (not this bike, it was for my chopper that I lost last year).
'09 Orange Copper Custom. Debaffled, 170/80 - 15. Bags, and shield.
Gone but not Forgotten - '09 900 Custom SE. Debaffled. Avon Venom 90/90/21 front and 170/80/15 rear.