One of the Freefly Distributors, Cédric, at www.1001copters.com looked at what he had and built a solution for hand holding an existing 3 axis gimbal using Radians, maximizing his investment. While he says he isn't a movie maker here's his video and BTS. His background note said "Everything made with Freefly system (clamps, press nuts,...) I wil had some Moto handle instead of foam one because when you will have to carry a 2kg payload plus the rig and the cinestar 3 axes and the battery, and the monitor... it will be a massive weight." Nice job Cedric! Get in touch with him if you want further information.
That's pretty damn impressive. I was wondering how they did that pass from one floor to the next. Wow.