The largest dome stadiums for baseball are probably all in Japan. Since pretty much all of them are currently in use and thus subject to license, the mod community can't touch them. (This was an issue from last year, and you might have missed it if you joined the community recently)
Meanwhile, a quick update on Sydney Cricket Ground. I'm still building the main structures. The more complex and most interesting parts are going to be done soon - bottom area of the screen shot here:
