I really fail to see the point you're trying to make here. The hypervisor and vSwitch merely provide layer 2 forwarding logic. It's at the discretion of the endpoint (read: the guest OS networking stack) to generate frames of whatever size and send it down the virtual wire.
Even if the guest OS detects that a NIC/driver is capable of utilizing jumbo frames, every OS that I know of will default to the ordinary MTU of 1500 bytes unless configured otherwise. You can't expect the hypervisor to magically interfere with the networking stack of the guest to create frames of an arbitrary size without the guest OS being aware of it or being configured for.
