I have a few steel ones that would work. You can either strap the chock down or leave it loose and strap the bikes down the the normal spots. I actually used it a couple times to move my street bike
I wonder if something like this would work - it looks like there are just two inline attachment points on it?
Edit - On further investigation, the rear attachment points won't work. I am sure you could rig it to work, but not sure if you'd feel like your bike is safely secured!!