That

...Is an incredibly good idea. That is going to look SO much better. I can see it already.

Perhaps there could be a second "layer" of objects- ones not affected by the light-source polygons?
That way, we could have things like LED lights (or nightvision goggles) that just look bright in the darkness, but don't actually give off a lot of light.

I'm thinking things like "You can see the zombies' red eyes in the dark as they approach."
The player would be aware of the zombies, but the machine gunners couldn't act without the light.