Basics

A Device used to move the weight of a heavy camera assembly to the user's back via a cable and support rod connected to a backpack like harness
Really not neccisary for small scale stuff, but useful for long shoots (either tons of takes, or things like live event coverage
Also more useful the larger the assembly stuff (if just a camera or camera + small shotgun mic not too neccisary, but if a large camera (Blackmagic/Red brand units), large lenses, a mic, a wireless mic receiver, and an audio reccorder, and perhaps a timecode generator are all strapped to a camera cage it starts to make sense
Also the brand name for this type of thing is quite expensive, and the amazon sold ripoffs break easily, so a quality cheap open source replacement may be a real hit in the indie film/small video journalism community and thus be a possible enterprise oppertunity

Industry Standards

Must be able to support a user choosable camera weight (possbly different models/mods for different ratings
Cable must auto tension + stay at the height the user hold it (not tug up (much) or fall down
Must be comfortable for all day use
Being able to break it down for transport/storage also seems like a neccesity
Also different sizes / heights needs to be a build option

A prepurchased/modified external frame hiking pack frame may work
Can 3D Print and/or CNC adapters + extra parts
Also perhaps extra cumfort features via either foam inserts or something similar, OR flexible filament prints

What wire/cable type?
Pulleys or tubes?
Use some sort of rock climbing style locking carribiner for attachment to the camera rig adapter for easy, yet secure swapping perhaps?

8What to use for the autotensioning roll? Spring of some sort? Also how does the adjustment mechanism work