The restriction on the use of the Virgin name due to SIA's investment in Virgin Atlantic runs out in August. The word in this part of the world is that the current crop of Virgin Blue Holdings airlines will be re-branded under a single name of Virgin Australia.
I think Virgin America is too young a company and already has enough on it's plate with making a name for itself in the US, to start looking at Trans-Pacific ops. It's taken Virgin Blue 10 years to get to the point where they can start doing Aus-US in widebodies.