I designed this for a friend that wanted to be able to mount a headlight on her Trek Speed Concept for early morning rides. It clamps around the aero bar extension
...Plus and uses zip ties to hold it in place. On top it accepts a K-edge insert to hold a Garmin device. I decided to use the insert because she currently uses an older forerunner device that mounts 90 degrees rotated from current Edge devices. This way if she upgrades to a newer device all she has to do is rotate the insert. On the bottom of the clamp is a GoPro style mount that will allow her to use a Bontrager Blendr mount for her Ion headlight (or any other accessory that works with that style mount).
I don't have a 3D printer of my own, so this was printed by Shapeways.