Most of the cool code that we implemented was dumped on the floor. We had an experimental feature that would play a varying tone (frequency and amplitude) as you moved the mouse around and got close or over certain controls. The idea was to give a way for non-sited folks to explore a GUI. It worked so much better than the final thing that was shipped which just read all the controls in x/y order in the currently focused window.
I eventually got off that contract and I was amazed that Vista was eventually released.