ARRI makes a wonderful system that is actually integrated directly into an Alexa Plus or Studio camera. Other cameras can work off a small box called the UMC-3. You can see a wireless in action here on a Alexa EV with an Alura Zoom lens.
Did you know that wireless tech for cameras was inspired by Radio Controlled cars, airplanes and helicopters? See www.rccaraction.com for all the latest R/C toys for the geek in you.