Doesnt Virgin have a tie up with National Airlines, maybe they could be a candidate?
Then there was rumours of Virgin buying parts of USAirways, presume the "shuttle" would be the one to procure as to gain access to lucrative slots at the major airports.
But buying an existing airline would also bring with it existing higher operating costs etc
Time will tell but like Virgin Express, I just wonder if there is further room for a low cost operator or have they missed the boat?