Modifiable keyboard layout backlight
Working as a programmer (and not only) in non-English speaking country makes one switch (rather often) the keyboard layout - from English to native language and back. And very often while typing fast, how irritating it is to 'discover'
that you actually haven't switched. If there were a keyboard that would illuminate the current assignment of keys
(English or native language) it would kill two birds with one stone: help using keyboard at night and save time and nerve for those using two languages alternately and switching between them.
Reward: a keyboard described above