I have come across a massive office park development on the far NW side of Austin, at the SE corner of the US 183/SH45 interchange. The development, which will eventually include twin 15-story buildings, is called Aspen Lake, and will be built adjacent to and surrounding the existing 10-story Tower of the Hills. Aspen Properties is the developer, and are currently building a smaller 4-story office building on the site (under constructin now).
http://www.aspen-pro...n...8&Itemid=33
Here's a conceptual rendering:

Aerial of the site (an abandoned Target store was recently demolished)
Site Plan
I'll post more info as I come across it.