Whoa. Bad idea! You don't want to mount the same volume across 13 hosts without some sort of control. Think of it this way, what if they all write to the same blocks at the same time? Yeah yeah, file locking and whatnot, but still, this is a recipe for disaster and data corruption. If you want to make a single volume accessible to multiple hosts, Xsan is the way to do this (though not with home directories) as the metadata controllers will mitigate access.
Why do you want one share to be accessed by 13 xserves?