Where have all the MVNOs gone?

Anyone know where all the likely MVNOs have disappeared to? It's a question being asked around the mobile industry.
"I'm pretty sure you'll see the first MVNO within the next six months," John Doherty, chairman of Comreg, told me today. "The logic is inescapable."
Alas, Doherty couldn't say which of the various contenders the first one might be. It's six years since MVNO hype started in Ireland.