Gotta look at Small Tree Communications and their ETHERNET SAN solutions. This will allow all the machines to be connected to shared storage via Ethernet. Mind you, this means not only getting a large RAID for storage, but also a computer to connect it to (MacPro) in order to be able to share that drive...and an Ethernet router. You cannot have shared storage capable of playing back video on multiple machines without having a server.
Off topic, but might be of interest to you. I'm selling my EdgeCore ES4524D switch which you need to do the shared storage. My set up is with Small tree equipment. I'm upgrading, hence I'm selling this switch.