We all have copies of eachother's saves, wheter we release them or not will depend on whether we can figure out who built what, get everything properly labeled, and see who does and doesn't want their stuff released.
This is making assumptions though. I know that I've named some of my builds random_build_15, and given them descriptions like "asdgf" and "cityv2 includs stuff", that no one would understand. And I was assuming that the other beta testers probably did it too.
We can probably include Beta City, the Ice Palace, and some random arenas for deathmatches. If not in the game, then certainly as an extra download.