Sketched up this little handlebar mount to fit the Polaroid Cube action camera. It is designed to fit oversize road bike bars (31.8mm). Run two zip ties through it and zip tie to the bars. It also takes a 10mm Diameter x 6.3mm thick magnet to help secure the camera.
Prints without support if you lay it on its side. (support will mess up the zip tie route)
Standard Liability Statement: So far this has worked for me, but like anything on your bike, failures do occur. Use at your own risk!