You can also use Fully tagged 802.1Q VLANs. I don't think this should affect the performance. The decrease of the ethernet payload between the switch and the initiator is only 4 bytes (so it's a loss of payload of less than 0.045% for 9000 bytes large frames)
Moreover, the presented use case contained a target with tagged VLAN on the target side, so I am not sure this would havr any impact at all.
Never the less if this is worried, maybe you can also take a look at non 802.1Q VLANs (macvlan on linux?).

Cheers, Alex.