Chicago:

Yojimbo's Garage (the one and only)
312 587 0878
1310 N. Clybourn, Chicago, IL 60610
http://www.yojimbosgarage.com
- plenty of track and Marcus is the man.

Upgrade Cycleworks
312 226.8650
1130 W. Chicago Avenue, Chicago, Illinois 60622
http://www.upgradecycle.com/
- carry track frames (Cinelli, Soma, etc) + track stuff in store

Uptown Bikes
773 728-5212
4653 N. Broadway, Chicago
- for the conversions, odd parts, cheap parts

Cycle Smithy
773 281 0444
2486 1/2 North Clark St, Chicago IL 60614
http://cyclesmithy.com/
- limited track stuff (cogs and lockrings), and off the shelf track bikes (Bianchi, Cannondale)