Event Bus with events for storage manipulation (e.g. queue insert) in order to avoid poling.
This is a great suggestion Vincent, at this time however we are working on improving the reliability, availability and other messaging channel aspects with Service Bus but are considering ways to improve such scenarios
Vincent-Philippe Lauzon commented
You can read about the suggestion in more details on: http://vincentlauzon.wordpress.com/2010/08/04/event-bus-in-windows-azure/