Just an update on this... I bought the same unit as 01marc linked. I submitted a review and they mailed off another camera system. Just received it today. Took about a week instead of prime 2 day. I was hoping they would send the same unit again. However, they sent a "wireless license plate frame camera"system without a monitor. This kit uses an app and your cell phone.
Doesn't quite play as nicely into my "4 camera/ dual monitor"idea but free is free.
Curios to see how it turned out for you 01marc