That's handicapped... If we made you a script so that only you could build, then it would not be ANY fun to be on your server. And then other people would start using it..
I say this is a dumb idea, and if you don't want others building on your server, then play like Riddler and go alone on an offline server.
You do realize that if you don't want other builds cluttering up your build, that you can just DELETE other players bricks before you save for the day right? There is no need for a no-build mod.