Lumbar packs sit lower on your back , maybe you can set up the shoulder straps to Be Much longer
so the bag can be lower on your Body.. + augment your helmet mirror with another one on the handlebars.
can you look under your armpit to, directly see behind you, while in the drops?
Maybe the Google glasses will allow a rear view camera feed to be monitored
in the screen image?
of course as I found with the little stick on inside your glasses Mirror ,
after the 18-35 year old market target everyone sells to, is aged past ,
The only people able to use this stuff will have to be quite nearsighted..
the whole Bifocal and I need reading glasses folks will be SOL.