Art.Lebedev says that the OLED keys in the Optimus keyboard will have three types (OLED, backlit and regular plastic keys). They will also be swappable. They will sell several configurations of the keyboard (for example, where only the 'F' keys are OLEDs) with different prices. You will then be able to 'upgrade' some of the keys if you want.

Read more here (Optimus blog)

Kyulux - Hyperfluoresence OLED emittersKyulux - Hyperfluoresence OLED emitters