The Cisco Nexus 1000v is a virtual switch that runs in VMware as a VM. Are you planning or currently connecting your ESX hosts directly to your Nexus 7ks? Do you currently have the 1000v's running now in a vm cluster? If not I'm guessing you have your vm cluster doing standard switching and you are wanting to migrate onto the 1000v? What kind of hardware are you running your ESX hosts on? What version of ESX? What version is your 1000v running?