I would think that the plane would have to be separate to Virgin Blue as the Virgin name cannot be used internationally.
The plane I would guess would be fitted out similar to that of Virgin Atlantic giving Aus-USA travel on an aircraft with premium economy. Air New Zealand have their business premiere fitted out similar to Virgin Atlantic, there might be some restrictions on what a new carrier could use. Maybe the plane might be an ex VS plane.
VS could codeshare giving VS around the world flight number.
It will certainly bring the airfare prices down.