I have written a Javascript routine which displays a list of the available access keys at the bottom of the page.
Maintaining a list of access keys used for each individual page was going to be a tiresome exercise. As Javascript can interrogate a page for this information, it seemed a little silly manually creating the same result.
So, I give you access_keys, an unobtrusive Javascript routine that searches for and displays access keys that it finds at the bottom of each webpage. Now available on GitHub with full instructions.
Thanks go to Radio New Zealand for inspiring this effort and then releasing it to the world.