Adding a rear view camera?

(I have read some of the postings about adding a camera to Gen 3 Prius)

I am waiting for the 2012 Prius to arrive to buy my first Prius (and first new car since 1981) because I've read that the level 2 will have the large touch screen. But the level 2 won't have the rear view camera, which I've been told is very useful and safer.

Reading here on Priuschat it appears that there are lots of after market options for cameras. The camera is about the only thing that I really care about that would make me want to go to level 3 and if I install an after market camera I might consider staying at level 2 to save money.

A few questions:
I thought the stock camera was mounted in that black plastic on the roof. Apparently after market cameras are mounted near the license plate. Is there already wiring in place to get from the camera to the display?

These after market cameras for this connect to the touch screen display, right? We are not talking about a separate little monitor clipped to the dash like you'd buy at costco? How do you connect to the display and what do you have to do to set the display to start using the camera?

 

Here's what I read:

2012 Prius Mid-Cycle Refresh Official Details | PriusChat

"There’s big news for the 2012 Prius in the audio/infotainment area, with new standard systems for Prius Two, Three and Four models. The Prius Two, features a new Display Audio touch-screen system with a 6.1-inch screen. The AM/FM CD player unit offers MP3/WMA playback capability with six speakers, a USB port for iPod® connectivity, auxiliary input jack, Bluetooth® hands-free phone capability and audio streaming. The display also provides vehicle information and allows the driver to customize vehicle settings.The Prius Three adds navigation and Entune, plus an integrated backup camera display, SiriusXM Satellite Radio capability, HD RadioTM with iTunes® Tagging, advanced voice recognition and text-to-speech with programmed and customizable text responses. The Toyota Entune system is a collection of popular mobile applications and data services, with three years of complimentary access. Once a smart phone is connected to the vehicle using Bluetooth wireless technology or a USB cable, Entune’s features are operated using the vehicle’s controls or, for some services, by voice recognition. Entune offers mobile apps for BingTM, iHeartRadio, MovieTickets.com, OpenTable®, and Pandora®. Entune data services include a fuel price guide, sports scores, stocks, traffic and weather."