Have a look here. I think I found the parts for panoramic view:
CAMERA & REAR MONITOR DISPLAY. Toyota 4Runner | Toyota Parts Center Online
If I'm doing my math right, this ain't cheap. I figured the head unit would do the work of processing the images and working the camera but I think there is a separate computer.
It won't be long until some aftermarket guys find a way to replicate OEM for a fraction of the cost. I hope.