I think it's a great idea. But I have something to comment:
If the "winner" of the design contest will be the prototype for all of the securtiy force team dudes, we should think about using parts that don't need TOO much modding, parts that can be found easily and parts that can be used to army build these guys. By the looks of it, this project is going to be huge so we will need HUGE numbers of army builders I think.
Oh, and I don't think I 'll have time to participate and enter a custom, but I might find the time to doodle a design for one of these guys, is it ok if I just post a drawing when it's done?