Unfortunately for Ronin and Movi, they don't run on SimpleBGC ;-) But the Turbo Ace Allsteady gimbal's do and are fully licensed with Base Cam to sell their gimbals!
Turbo Ace has created a mount for all of these gimbals to dampen the 4th axis while walking and running. Check out their Kickstarter campaign to see the 4th axis mount.
Interesting, I think its a big step to improve the quality of stabilization. I suppose its not 'active' - it contains spring and dampers? Did you considered active (motor-powered) solution?