Love SS off road. My primary rig is a 29er from Scott Quiring called a Qball. Some pix on my blog of my beloved Qball.

Also have a 26er, a Fetish Fixation, which I am in the process of rebuilding into a 1x7 with front Suspension and going to sell. Here it is a fixed commuter and an SS 69er. The 69er config was by far the best but I want to try a steel frame. Aluminum is too harsh.

My next SS/Fixie project is a 1992 Bridgestone MB-5 rescued from the town dump. Since it has vertical drops I might try to do a Ghost Chain Tensioner. I have the bike about half way stripped. I am thinking drop bars, just not sure whether to use a flared set, or go with mustache. In order to do so, I need a new quill stem. I also have a Surly Fixer adapter that I am trying for the first time, so it will be a bike of many firsts.

Off road SS is a blast and fixed gear is totally wild.