I need to mess with the mount more but here is one to start with:
I don't know if I trust the mount on the axle sliders. But it does hold well. I will have to figure out a way to give it more to grab a hold of.
Also If you only leave one bolt in the aluminum beam to mount the camera it allows you to pivot it. I think if there was a way to pivot the beam and feel safe about it you could get way better shots.