I went with an EighthInch Scrambler for my first SSFG bike. $600 shipped, and you get to customize everything on it, so right off the bat, you get what you want.

I have to admit though, sometimes I wonder if I'd have saved more money by getting a Kilo or Motobecane Track from Bikesdirect, then upgraded whatever parts I wanted afterwards. Haven't done the math just yet. Anyways just mentioning the possibilities... better to know all or most before jumping at one.