I just came across a press release announcing this new vest / camera holster.
The Cotton Carrier system allows you to hold two cameras with medium length lenses. Looks like it fits nicely on the body.
As I am looking at the possibility of carrying two cameras with me: one with a long lens (either my Sigma 150-500 OS or a Nikon 200-400 rental) and a medium lens (a 70-200 VR that I plan on buying).
For one body, I have a nice Kata neck strap that attaches to two D-rings on my bag, thus putting the weight on the shoulder straps rather than the neck. I am fairly confident that this setup would not work with two bodies.
Of course I could ask my wife to hold one – and shoot with it.
So the quest is on!