No cheats, hence it is made of cobblestone and not as pretty as yours. It took a long time.
The world is tall enough to hold the next size up, but you'd need a big hole, and it would be insane to attempt it without cheating. With an editor which can cut and paste regions, it would be very fast.
I used TooManyItems for the iron blocks and /fly to take the screenshots
Here is the construction process:
A frontal view:
Glass Dome Project
No cheats, hence it is made of cobblestone and not as pretty as yours. It took a long time.
The world is tall enough to hold the next size up, but you'd need a big hole, and it would be insane to attempt it without cheating. With an editor which can cut and paste regions, it would be very fast.