How to live stream 4 cameras to a flat screen TV
You need something like the Blackmagic Multiview: https://www.blackmagicdesign.com/products/multiview or Matrox Quad-Split http://www.matrox.com/video/en/products/microquad/ or Decimator MD-QUAD http://decimator.com/Products/MultiViewers/MD-QUAD%20Quad-Split%20MultiViewer/MD_Quad.html

These units take HD-SDI input and can then display it on a HDMI (or SDI) display however you like.

So grab as many cameras as you need - you can decide what quality camera suits your needs. Get cameras with with SDI output for long cable runs. If they don't have SDI, you can get HDMI to SDI converters. If an SDI cable isn't long enough, you can get SDI/HDMI to Fibre converters that let you run fibre optic cable between your cameras and a multiview. 

Any half decent multiview will let you use a computer to re-arrange the placement of the images on the screen.

Good luck!