Searching for megastructures, dyson spheres and other things, i've foun this:

http://en.wikipedia.org/wiki/Globus_Cassus

Basically, the idead behind it is to transform the Earth in a Megastructure, bigger than Saturn, but hollow inside, and people will lie in the inner side.

The idea was proposed by Christian Waldvogel, achitect adn artist, and presented at the Venice Architecture Biennale in 2004.



The cables that appears in the image, utilized for the transmition of raw material is very like Blame/Noise. Actually, Blame's Meagstructure is a Globus Cassus that have gone nuts. =D

More images at:
http://www.globus-cassus.org/press/

in Alita: Last Order volume 3 are also ideas for megastructures, they based on the concepts of Paul Birch.
It contains ideas for nearly all Planets in the solar system (but all are seperated, not like in Blame or a Dyson sphere)
its a metal- bubble around jupiter (to use the surfcae), huge solar shilds for venus, to gain energy and protect against the sun, the known installations on earth (orbital ring and stuff) ah and more, i dont remember it.

but i didn't find any in wikipedia or google, as i searched. hm.
(so i have no pictures, except you look in your own last order manga, volume 3, somwhere around the middle of it..)

I saw this a while ago, and it seemed pretty cool. The only problem with it is that it would be disastrous if the people making it screwed up :/