Our ATV just has two switches...one for the LEDs (basic at beat, but whatever) and one for the siren (58 watt?) - It's a remote unit set to yelp. There's nothing fancy about 'em...two big (waterproof?) toggle switches on the left side of the gas tank towards the front. They just used the existing holes in the body and mounted the switches. It's been that way for about 6 years now w/ no issues.
I'll try to get pictures this afternoon. Certainly not impressive or a "Cajun"-worthy install (or any of the other guys I'm impressed by on here), but seriously, the LEDs we have are plenty sufficient for riding trails and making an occasional traffic stop on a dirt road. (Unless something is really f*ed up, we don't pursue or run code on it.)
Off topic, the LEDs are TIR4s. I keep changing them to "all on" flash patterns, and some jerk keeps changing them to splits (2 and 2) patterns. I'm gonna change 'em to an "all-on" and snip that yellow wire at the base someday soon....