I did this with DB ages ago, you simply set up a light to face an object at all times (ie, repositon it per loop), adjust the distance so its projection elipse matchs the rough shape of the object and make it negative.
I could give you my DB source code for the game i made if you want, it works, i think.
Problem is its part of a game, and since i switched to DBP i cant compile it
(too many errors and glitchs when you use DBP..).
"The man who says it cannot be done is generally interrupted by someone doing it." ~ Elbert Hubbard