The white paper at
has a section that describes an "Interface Virtualizer", which when deployed within ESX along with an appropriate physical switch (that supports "NIV"), would offload all "vSwitching" to the external switch.
Is this functionality available today? Is it a mode in the Nexus 1000v, or is it a completely different product / usage model? How would I go about configuring it?
Yes, it is available today and is implemented in UCS using the UCS blade adapter Cisco UCS M81KR Virtual Interface Card along with the Cisco Nexus 1000v VEM on the ESX host.
Watch my video on how to implement this.