I got in touch with Brett regarding his products and the need for something like this for boom operators. He was great in communicating about his upcoming redesigned chest pack and was good enough to push the production through so I could get hold of one before the start of an upcoming job.
After a few weeks of use, I'm happy to report it lived up to my expectations and is the most useful and comfortable pack for boom operating I've found yet. There are no products like this with the specifics of boom operating in mind, but this is the closest yet and is also very comfortable to wear all day. Very well made, and locally to boot.
Would recommend this chest pack to all my fellow boom operators, but also would be very happy to discuss the specifics of a potential future pack just for us boomies!