ok, I just read this in scott lowe's book and now I'm curious again, and want to test this:
Normally, vSphere requires that you mount an NFS datastore using the same IP address or hostname and path on all hosts (.... However,In vSphere 5, you [can]use a DNS hostname that resolves to multiple IP addresses. In this case, the vSphere NFS client will actually use all the different IP addresses behind the hostname. This is the exception to the rule—in this sort of configuration, the NFS client could end up using multiple links in a link aggregate for increased overall throughput between the ESXi host and the NFS datastore.
My plan was to simply add multiple interfaces to my virtual storage server, and give them various different IP addresses, and then statically create multiple datastores on the ESXI host which directly reference the various IP addresses... The actual exported nfs filesystem on the nfs server would be the same, but with multiple IP addresses, and multiple virtual addresses, I would guarantee that a single connection across the gigabit physical network would not be a limiting factor. however this seems better - no need for multiple datastore definitions.