OK, I've updated the functionality concerning the mouse -- I hope it's a start! =)
When you update to the latest GitHub version, buttons and sprites have a the new property "useHandCursor", which works just like in Flash. Hovering over a button will transform the cursor into a hand.
This is enabled by default on the button class and disabled on the Sprite class.
Furthermore, if you want to handle a classic "mouse out" event manually, there's now a new method in the TouchEvent class: "interactsWith(target:DisplayObject)".
When it returns true, the mouse cursor is either hovering over or touching the target. When it's false, the mouse has just been moved away from the object (hovering), or the button pressed over the object has just been released.
That should make it much simpler to create custom mouse logic.
The demo SWF on the Starling homepage already shows you the new hand cursor over buttons.
I'd be happy about any feedback on that feature!