There's lots of them.
Pioneer has quite a few models with car play.
The camera switching is going to occur outside of the dash unit. If your current cameras go to your dash unit, then you already have the camera switcher. It's basically 3 inputs with one output that goes to the dash unit. If not, you can pick one up on amazon for 25 or so.
I can tell you this, car play is a pain in the rump. Great concept, but a hassle In reality. It more or less takes over your phone.
Example: open maps on your dash unit. Great a perfect map (except the dot showing you is big enough to cover the important info). But any way, let's say you want your copilot to open say, an audio book.... map gone. Got a text message? Map gone, and Siri just blindly starts reading the message to you. Need to do anything else with your phone? Map gone, or any other app for that matter.
It's ok, but leads to some frustration.
RVM#78 - -USAF- F-15 Eagle Radar Vet
2005 Fleetwood Revolution
'12 Chevy 2500HD
'15 Airstream International Signature 27FB