On the early SM 420s there was a lever arm that attached to the shift handle that depressed a simple 2-wire push button switch to operate backup lights. It would be a very easy project to fabricate one of those from parts available at the local hardware store. I've used a pair of fog/driving lights attached to a rear bumper to make VERY efficient backup lights. A push button wired into that circuit was also effective at getting tailgaters to back off a little!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!