Info on adding a datastore to multiple hosts in a cluster via PowerCLI:

http://www.vmware.com/support/developer/PowerCLI/PowerCLI41/html/New-Datastore.html

I should be able to modify the code in example 2 to add NFS storage to a group of hosts:

Get-VMHost | New-Datastore -Nfs -Name NFS1 -Path "/mnt/nfs1/nfs11/test1" -NfsHost 10.91.246.21
Looks easy, right? How hard could that be? ;)