More light on the screen usually means less visibility around the screen. My laptop has a bright 17" display, yet I cannot see any keys

I see them best when I switch of the screen
Glow in the dark (aka phosphorescent) is indeed a bad idea. When I need light on the keyboard it usually have not had any time to charge beforehand. Fluorescent (the streetsign-effect) now would be something different if the light of the screen suffices to activate the keyprint.
Optically speaking the approach of the Razr Lycosa is beautiful (the one posted by pengo). Technically though these keys are terrible to see when NO backlight is switched on. It does not matter on a desktop but matters a lot on a battery powered device.
Taking the current design it probably would be easiest to use a transparent white rubber as a mat (for light transport), clear (or at least kind of clear) buttons with black letters. This way the keyboard is still readable without light. It might look crappy but will work
If you embed transparent letters in a solid key you probably cannot read them anymore (as they are dark without light from below!). Also this is more complicated (if possible at all) to produce with the current design as you have to get the light to the middle where you have the "switch" of the key.
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One comment on the (nice) Rii Mini:
That looks a lot like a mouse-button-tech-keyboard. This is ok for a few types but the hell for real writing. If you ever tried the N900....not convenient. The current Pandorakeyboard is miles ahead, even though I would prefer "softer" keypresses. But there have been pages of ideas way back in 2008 about that topic
