Battery powered lights are a good alternative solution, especially if I could get DW to turn them off! Never fails, I have to replace batteries EVERY trip because of this. so +1 to the hard wired solution.
When I do mine, I'm just going to put an entirely new fixture in (which will include its own switch) and "piggy back" the wiring from an adjacent fixture. All LED, so little risk of overloading a circuit designed only for one light...
2014 Jay Flight 28 BHBE
2015 RAM 2500 6.4L HEMI, Tradesman 4x4, 3.73
Blue Ox SwayPro (BXW 1503)
Upgraded from an REI internal frame backpack and a Eureka 1/2 dome tent!