True and sad, front LED boards would be really cool. Though I believe it would be pretty complicated. When you lasered out the letters for example, you would have to take care of not doing it both on the front and back of the key etc.^^
Actually, I also like completely unlabeled keys a lot, a LED model of this with transparent non-labeled keycaps would be pretty funny... Though the LEDs mustn't be too bright I guess. Dunno if it would look good, but exotic for sure.^^