This area is really starting to get exciting, so I decided to compile and count the proposed mid and high-rise buildings.
Tysons Corner Center Redevelopment: 10
http://www.tysonsfuture.com/flash_co.../Site_Plan.jpg
Tysons II Corporate Office Center: 7
http://www.slideshare.net/nvar.com/f...a-presentation <-----Slide 19
Towers Crescent: 3
http://www.slideshare.net/nvar.com/f...a-presentation <----- Slide 18
Tysons West Promenade: 2 (not shown on website, they're in phase 2)
http://www.tysonswest.com/animation.html
Tysons Demonstration: 14
Video (click demonstration project)
http://www.georgelasgroup.com/portfolio_commercial.php
Capitol One Campus Mixed-Use Development: 12 (from what I can see on the site plan)
Park Crest (2 buildings already finished): 4 (planned)
http://www.metrodcliving.com/urbantr..._market_p.html
In total, thats 52 mid/high rises planned or proposed for the area!