A better option may be to use IP Cameras, you can then only run one line from the cameras to the recorder.  If the cameras are a distance away, with IP you have the ability to also shoot across a wireless link ( I have done that  a lot lately).  Here is how I see your IP set up being 
  
IP cameras running into a POE Switch 
  
One Cat5e from the POE switch to the NVR 
  
Keep in mind you will always need electric where the POE Switch is.