This is what I'm talking about:
An entire world of that^
Generating 500x500 chunks currently takes 70 minutes on my PC. I'd want the world to be at least 1500x1500 chunks. So that's about a day's worth of pre-generating worlds. Unfortunately I can't generate bigger then 500x500 maps currently. Stitching the worlds together is going to be a pain...
Also, we may want to add a 'flying machine' plugin to this world.