How about we create a brick that acts as a light and creates shadows?
If you're concerned about the light updating every millisecond or something and want to point out how that'll be a frame-killer, what the sh*t!

Obviously there will be optimization, I'm sick and tired of making suggestion topics and there's always a smartass saying how it'll do this and that and won't work well.
Perhaps there could be a boolean that turns on and then when it turns on the lights update and then the boolean turns off again and then waits for a number to be 10 or something and then the boolean turns on when it's 10 and then the number resets back to 0 when it reaches 11, and this number goes up.
And maybe when you're closer to one of these lights it doesn't have to be 10 and instead it's 5 and it resets when it reaches 6, this way from afar it updates slower, and then when up close it updates faster and more smoothly... But one problem is light de-rendering range is a little short so it would be somewhat irrelevant to have a shadow LOD system since you cant see lights from afar.
Partially Ontopic: Idea: Light LOD System, from afar they're low quality shader-based lights, and up close they look like default lights.
This way we won't have that weird light disappearing problem and it won't break the bank when it comes to performance hit.
Or maybe just allow people to adjust the light de-render range.