Austin101 on C-D did a really cool thing kinda like this last week.
He just used blocks to represent the buildings but got lots of cool stuff that is either U/C or planned. He did it like that with lost of views and what-not so you can see the heights of how things will/could look.
Defiantly worth taking a look at his work. It is really fun to look at. =)
Just be warned... it is C-D.
http://www.city-data.com/forum/austi...e-skyline.html