It is most definitely possible to convert a freehub to fixed. Locking up the pawls on a Neuvations R series hub with a filed down section of spoke (just so it wouldn't elevate the pawl preventing the insertion of the body (no other interpretations are necessary. If you proceed to interpret that in a non-bicycual way, go **** yourself) into the hub) under each of the three pawls. After 3 km with some skid stops, there was no slipping and it gives me the magical choice of any chainline and any cog that I want, too bad it ain't track legal.