I'm admittedly biased toward the Bridgestone RB-2, but they are a great bike that is often overlooked by bidders gunning for an RB-1. Most go for under $300, even in really nice condition. There's a few up now, but the closest to your size is this 55cm. I'd keep my eye out for one in your size.

http://cgi.ebay.com/Bridgestone-RB2-...QQcmdZViewItem