I'd prolly install a 6v 4-way flasher, a 6v center brake light, a 6v backup light, 2 side view mirrors, bendix brakes and assorted other accoutrements first, 8^)
sure do.. It's called a rear view mirror.You don't have a car with one, do you?
Try having a hunt for a USB powered camera. It's 5 volts, you might get away with that.
Alternatively, you can get 6V to 12v step up converters. They are fully isolated and can be used to drive 12V components, depending on power rating.
This one is advertised at 10A, but I would take that with a boulder of salt.
https://www.ebay.com/itm/311962628209?hash=item48a26bf071:g:pAkAAOSwC11Zv5bG