Comment 13 for bug 773078

If it helps, from http://www.apple.com/accessibility/macosx/physical.html

"When Sticky Keys is active, OS X visually displays each modifier key in the sequence in the upper-right corner of the screen, accompanied by a sound effect, so you can verify the sequence and correct it (if needed) before it’s entered. When you press the last key in the sequence, OS X plays a sound, enters the keys as a chord, and removes the visual representation from the screen."

Note that both of those behaviors are configurable. Key modifiers are actually overlaid on the screen, rendered semi-transparent, and can be dragged around with the mouse. Amazingly, I could find no screnshot of OSX online, so I include one here:

https://plus.google.com/photos/102359747730797411333/albums/5834442142323280017?authkey=COm2pcqp847vLA

Please let me know if that link doesn't work. I shan't remove it, but you're welcome to re-host it somewhere more sensible.

I will reiterate that this is a serious issue for some, including me. It is the difference between disability and health. Currently, OS X and Windows appear to take such issues far more seriously - this has actually been a problem with linux (and thus Ubuntu) now for years. But if you got the right person (perhaps the person who coded sticky keys in the first place?) I imagine this is a couple hours of work to address.