As I posted here a year or so ago, my 60 model Jeep did not come with backup lights.
I got tired of replacing tail light assemblies.
They did not cost much, they were generic NAPA tail lights that I bought a case at a time.
Think I paid about $3 apiece.
But, trying to turn around in the woods at night would usually cost me 3 or 4 per year.
My motto was "Just back up until you hear something crunch".
Finally I mounted a pair of those 150,000 candlepower 7 inch JC Whitney driving lights on the back.
Ran it to a switch on the dash.
It was great for turning around in the woods at night.
And, because I was young and stupid, I found it very useful for those guys who would run up behind me and put their high beams on because I was driving too slow for them in town.
They only did it once.
In your case, if you do a lot of turning around on trails at night, I would consider mounting a pair of those 55 watt rectangular flood/fog lights in the back.
Just be sure to run them through a relay!!
There is no sense in having to replace a backup light switch, maybe some wiring, and then have to put the relay on anyway.
I would let the backup switch fire the relay only, and run a heavier power line from the power source to the relay and then heavy wire from the relay to the lights.
Here is a kit that probably has what you need.
http://www.amazon.com/KC-HiLiTES-51..._6?s=automotive&ie=UTF8&qid=1291840351&sr=1-6
Probably find it cheaper somewhere else, or as separate parts.
But, it only has to prevent you from backing off into a stump hole or small creek to pay for its self.