Actually, I just made my own Crossover RP almost an hour ago. It's, kinda similar to this because I liked the concept, I guess. But it takes place on (ambiguously) Modern Planet Earth, it has rules and won't just be mindless anarchy and a slow descent into madness. It's freeform in that when somebody does something crazy important, it counts as a "Significant Event" and if your character say, trys to nuke another country, I will (try) to have said country respond in an appropriate manner. It's here, since there's no rule against plugs (I think): http://www.roleplayerguild.com/topics/32777/posts/ic