Since you say you have long legs and ride with the seat all the way back, you might want to avoid bikes with steep seat tube angles (not withstanding you wanting a more aggressive design). The Bianchi San Jose, the Raleigh One Way, and the Redline 925 are all commuter friendly single speeds with STA's around 72.5-73.
See this thread here a couple of weeks back on women's bikes, especially Skmetz's post in there:
http://www.bikeforums.net/showthread...f-a-bike/page2