removing/modifying falloff of lights

what I want to do is use a sot light, and or point light to define to the player an AI agents field of view (spot light to define an agent that has conical FOV, and a point light to define an agent that has radial FOV).

I will be using this to represent these definitions to the player (actual FOV will be code defined, and implemented), but I keep hitting the wall of light falloff (the rate, or function that determines how quickly the intensity of the light decreases from the source to the range of the light’s effect).

for those that are unfamiliar with the applications consider a directional light to be a spot light that has an angle of 180, range of infinity, and 0 falloff.

how do I go about removing, or at the vary least reducing the falloff of a light? right now I can move the intensity of the light to maximum, but for some colors of light this is not ascetically acceptable.

Bad news: as far as I know, you can’t. D:

Perhaps a different way of looking at it…

Instead of using actual lights, perhaps using a Projector with a cookie cutout, coming down from above?

Round cookie for an area, triangular for a ‘spot’…