Download leocad for these virtual creations there you can choose any colour you like- only problem with leocad is lack of some pieces but colors are completely free -you can use any of the given but strangely enough they aren't comletely identical to real lego colors here is a link http://www.leocad.org/
Hey guys thanks for the comments! To Robo Man: I actually have a noticable scarcity in bricks. Swash: The black bricks cannot be turned into dark grey because LDD does not supply the piece. Its either black or white! And Ben, the colors can only be black and white as mentioned above.