** UPDATE* I lost interest in the map T_T You can download the brushes in vmf format here** http://www.facepunch.com/showthread.php?t=916898
About the map:
** The map will be a construction zone (as the name suggests it) that takes place on top of some buildings and partially inside them. The map will have 2 versions, one for gmod (this one will feature the ability to go down on the streets and it will contain more rooms) and the other one for a multiplayer Source game.
**Initially, I wanted to make it a normal construction zone (like this http://www.bosai.go.jp/hyogo/3de/ephotos/elist_5/pc10_8.jpg), but then I remembered that Mirror’s Edge had some nice construction zones, also some nice cranes. So I searched for some images and I chose this :