I looked for a GTB for a LONG time before I found my Panasonic, and from what I recall, they're sized small. I may be completely wrong because I've never ridden one, but I nearly bought a 54cm and I'm 5'9. Please don't pay more than $300 for this frameset; the outrageous inflation on the generic track bike is 100% driven by the cult following behind these frames, when in all actuality, they're really just eh framesets. Look for a kinesis Pulse I'd say.
Actually, I just found this and it's telling me I'm dead wrong:
http://www.bikeforums.net/archive/in.../t-389541.html
You may want to send jet sanchez a pm.