"unexplored sky !"

I have an idea for a future sky update. Since the game offers so much creative 
freedom, why not create an area that's very difficult to reach? It could be called 
"Unexplored Sky" or "Mysteries of the Sky," whichever you prefer. In this update, 
we wouldn't immediately know what was added to the game, since Minecraft only allows 
you to build up to layer 320. Why not create zones above this layer? The blocks 
should be unbreakable; we could only create them using chests or mobs from the same 
area. The floor we could walk on should be called "Dense Clouds," and these would be 
special zones where we could find sky rabbits, similar to the "Aether" mod. 
The loot can really be customized, but an area where using the Happy Ghast or elytra 
is mandatory would be incredible.