Live Magic the Gathering Coverage

Hey guys so our local card store would like to set up some coverage for their big events in the nearby convention center. We have a decent budget and would like the stream quality to be the best it can be. We're starting from scratch on the whole thing. The question I am getting stuck on is how to use regular cameras/camcorders (instead of webcams for instance) for each shot (we would need one overhead, two face, and one for the coverage team for a total of 4 cameras), and jam them all into our PC. I assume we can't use USB, does anyone have an idea on how to stream live footage from these 4 cameras? Also, any other suggestions about the situation would be much appreciated. Thanks!

Desktop or Laptop PC?

Desktop can use cards like Blackmagic Decklink Quad (4 inputs) or Matrox VS4 (4 inputs and ISO recording as well). If your cameras are HDMI you may need HDMI to SDI convertors. There are 4 HDMI input cards but long cable runs can be dicey (although possible). Magewell has a 4 HDMI input card, XI400DE.