I could have built Rupture Farms in Single Player with INV Edit if I really wanted to, even before 1.8. But for the (rather stupid) challenge of it, it's being built legitimately on the multiplayer server in survival mode. It also gives people the opportunity to contribute to the project.
I fully intend to continue building when I'm done with the castle at Exoddus (intended to be a public building, BTW - Not just for myself) - The portal Havoc put in to it recently makes things a little easier. Stay tuned.