Many of us have been faced with situations when the keyboard did not correctly indicate what character would appear on the screen because the language of the OS (and, thus, the key layout) was different than the one the keyboard was made for.
There is also the matter of different programs using keys for different things.
Designers Maxim Mezentsev and Aleksander Suhih posted a concept keyboard on Yanko Design.
Rather than plastic with printed letters, or numbers or other characters on them, each key is actually an E Ink display that always changes to illustrate the effect it would have for each application being run.
In Word or other document writing software, the letters and numbers usually stay as they are, but S can change into a diskette symbol, for instance (CTRL+S is the standard “save file” command).
Check out the idea here. Maybe the world will get lucky and a real product will actually appear at some point.