Many are talking about Citrus engine which also uses Stage3D, Starling, Away3D, Box2D and NAPE. It seems like they are moving forward very fast. Citrus is higher level layer above mentioned libraries, which makes gamedev process easier.
Complete SWC engine with all extra libraries included in about 2.5 Mb available from downloads page and full API docs are easy to find.
Here is only one of many examples of how game may work if it is made using Citrus Engine.
New market files: Breakout Game Starter Kit | Top Down Shooter Kit