Anyone who follows Dinnerbone on twitter has seen that he is working on the lighting engine. Here is what he says about what the new, schmancy lighting engine could do: "Our engine supports fancy lighting control now, so that could be fun to play around with; one-way light filters, or directional light maybe?"
That would mean things such as one-way glass. Discuss.
Sounds cool, but what about colored lights? Will it be possible with the new engine?
Dinnerbone out of the blue just gave the option for directional lighting. With that, anything is on the table, especially an issue that Dinnerbone has personally commented on and knows just how much fan demand there is for such a thing. Personally? I'd bet that colored lighting will be worked on within the next two weeks.