Interesting. I read something similar not too long ago and dropped the idea of moving to a SAN. We had 2 servers as VM hosts running off RAID10 local storage. Instead we just invested in a third server (far cheaper) and re-balanced the storage so that each machine could replicate its VM guests on another machine. Server A runs its guests and replicates them onto Server B. Server B runs its guests and replicates them to Server C. Server C runs its guests and replicates to Server A. If a server dies, I figure I can just activate the guests on the server next to it and be back up and running. The time between replication updates is 1 hour which is reasonable in our SMB, though there is talk about making some of those servers HA. I don't know what approach I'd use then.
If you need HA then you make the leap to VSA. You...