iam currently creating a GUI for a kind of "rig" in the 3D Viewport (Not in the Blender Game Engine!)
and it would be an treat for the eyes to have highlighting while hovering over a button.
So how it should work:
How the "Button" (A Plane with an Text-Object) looks:
How it should look when you point with the mouse on it:
If this gets too complicated please tell me :)
Have a nice day!