I've seen wireless switches to control foglights on cars too. It keeps you from having to run a wire through the firewall of the car. One of those could be adapted to be able to turn the original ceiling light on and off. I believe Wal-Mart usually carries a version of this.
1999 Silverado 1500 ECSB 4x4 5.3/3.73s
2009 Jayco 32BHDS