if you are calling this an appliance, where in the code is an appliance required to be listed at all?
I wouldn't call it an appliance. Its basically custom casework, with a panel or loadcenter wired to some kitchen equipment.
I think it should be treated just like any other premsis wiring that the on-site electrician does. Just because they wire it before they bring it in the door doesn't mean its exempt from the code.