I got one of the dual shoulder ones from an online model aircraft shop. If I did it again, I would look at what the sound recordists use for their harness systems.
We use this one: http://smile.amazon.com/Secraft-Tra...=UTF8&qid=1422665707&sr=8-11&keywords=secraft If you buy it directly from Secraft you have several color choices. One of the clips goes onto the same place the neck strap clicks into and the second clips just clips onto the first one. Very adjustable for height, etc. We use these for our transmitter trays for flying all day too. Far, far better than the neckstrap.
Totally agree with Ben. Once you load your Controller with monitor, RX, V-Mount, etc. etc. it starts to get heavy and the neck strap isn't a great solution. We added a few anchor points to our Controllers - see pic: That's fun - image gets inverted on upload. Odd... anyhow... We mounted a small cheese plate on the top of the Movi which provides the room to add a proper monitor ball mount and separates the RX from the mass so the antennae can be properly positioned. Wow, that is annoying that it inverts the images. Anyhoo... We tried a number of small ball mounts but they all had the same problem - you could never tighten them so they wouldn't move. Then we found this great mount by a Canadian company - Cinevate - their Universal Accessory Mount: http://goo.gl/vi9zEm Simply awesome! Position, then LOCK. And it LOCKS! We then connect the entire rig using the three D-ring loops to a Porta Brace AH-3HD harness for audio rigs: http://goo.gl/mKUO4U You can literally take your hands off the controls and it stays perfectly balanced. No strain on the operator. And you're not struggling to balance the Movi Controller while trying to perform a perfect move.