For the surveillance look you would need a quad splitter for the cameras. This puts 4 cameras together on one screen.
The hardware that you find for this mostly takes composite video with bnc plugs as camera input. The output can be analog or digital (eg: http://www.ovation.co.uk/HD-Video-Quad.html ). That way you can use coax for cabling the cameras, which is good and available in theaters.
The not real time video can be played from your preferred player (could be Max of course). You can use one machine per video channel, which is probably the most stable situation although you can combine, and connect the output to switching/matrix hardware.
For instance, the above quad splitter outputs DVI. The most computer machines nowadays can output digital in the form of DVI as well.
With a DVI router like this ( http://www.kramerelectronics.com/products/model.asp?pid=2391&sf=236 ) you could do whatever you want the pro way. Mind you, these things can get expensive!
If budget is tighter you can have a splitter per projector, thus being able to switch between cam/video per projector (eg http://www.kramerelectronics.com/products/model.asp?pid=1712&sf=36 ).
(be aware that long DVI cabling can get pricy. If necessary all the above can be changed to analog VGA instead of DVI)
