Go to the "Spy Shop" on line. You can ignore the gizzmos for investigators if you want but look for "pinhole" cameras. Many different types, color cameras with night vision are less than $50, some are cheaper with wide angle lenses and the cannon style will have a narrower view. All weather proof.. They come with wiring plugs are different so hook it up yourself, only 3 wires and getting it wrong by trial and error won't hurt anything as they are very low mw devices, the feed either works or it won't and any camera they have can be used to any display screen/computer monitor or video camera.
I just got an Alpine GPS/Nav/stereo-phone system and the "spy cameras" work, I have a bag of cameras from surveillance matters and plane on putting a switch control panel on to select various cameras to my monitor, back, both sides and front. My system accepts 2 feeds so changing a split screen should be easy. These things weigh grams or ounces so you can just glue them into position, the cannon type have mounts and you'll need screws.