GUI Buttons and game objects?

Is it possible to drag a game Object into or onto a GUI button which the GUI buttons act as a grid for an example? And the game object locks onto the GUI button like the drag and drop functionality in flash?

Sure it's possible. (Game objects and GUI controls reside in different spaces, so you'll need to define specifically what the desired behavior is, but yes, whatever it is you're wanting to do, it's possible.)