Originally Posted by telenick
A good bike messenger, if anything, is fast. 29" (or 700cc) rims will be faster than 26" rims.
My choice would be a Surly Karate Monkey built SS.
i completely agree w/ this. go with a rigid 29er set up single speed. you will be fast, and the bike can take all kinds of abuse. remember, you'll ride in crap weather too, so if you are ss you wont have to worry about shifters/derailieurs not working...