camera for 04 Prius

My wife's Prius is an 04 with package 9 (includes nav system) and she would like me to research what it would take to have a camera so that when she is in reverse she can see on the MFD what is behind the vechicle. The requirement is that when she puts the Prius in reverse, the screen would automatically display the field of vision behind the vechicle and when she is not in reverse, the MFD display is normal. I am not fool-hardy but I would not have an issue with performing the modifications to provide this function. Has anyone installed the mods that enable this function?
Thank you.