Yes it can be done. I got a SAN from a supplier
http://www.2degreesfrost.com/ This uses SATA over ethernet and you need a copy of Fibrejet for each Pro Tols system that you connect to the SAN. We are running 3 systems, 2 edit and a Mix system, from the system with no problems at all. We can run complete Pro Tools sessions from the SAN over ethernet. You can use the spare ethernet port on the new 8 Cores so there is no need for a separate card. Setup is simple and the unit is relatively inexpensive compared to other Video SAN's.
Robin, who is the main person at 2 Degrees is very helpful, we took a punt on this and got it shipped to Australia and we have a spares kit.
hope this helps
Simon L.