I though about the shoulder mount option for a long time but it just wouldn't work for me. I'm over 6ft and the lead actress in the film is 5ft3. The shoulder rig also wouldn't work for walking and running like the steadytracker does. The more weight I add to the steadytracker the quicker I'm going to be fatigued so I have to keep the on camera weight to a minimum while still having all the accessories I need.
I use a DVRig Pro (with my HVX), which allows you to position the camera lower than your shoulder while still using the shoulder support. You can walk with it, but running would probably be too shaky. It's not as smooth as a steadicam, but it sure beats plain hand holding. The additional support points to the body and the mass of the rig helps reduce vibration. Also, the rig takes the weight of the camera off your hands and puts it on your torso, so you can shoot all day without getting fatigued. It's more expensive than the steadytracker, though. Something worth considering.