there was a time when cyclocross bikes were all made in the home not by a manufacturer. Not that long ago if you wanted to ride/race cyclocross you had only one option, build it yourself. I still follow that time honored tradition, mostly cause i'm a cheapskate.
when i started racing cyclocross, there was not a cyclocross specific bicycle available for purchase off the floor of my LBS. so i rode my mountain bike, the next season i raced i built a cyclocross bicycle. It was really pretty easy and cheap, and i still re-build a few for that specific use. I won't bore you with the technical details, except to say that single speed is good, cantilevers are not always necessary and lastly allow for mud clearance.
the little philly pictured here is an oldy but a good enough. i bought the frame for 20 bucks. i like old frames for cyclocross and single speed conversions, the key is the semi-horizontal drop-outs in the rear. i have tried to track down the name/brand, the closest thing is a ski clothing manufacturer. i assume it was imported in the 70's/80's from japan or taiwan and labeled by the importer.
it has mafac 'racer' centerpull brakes, modolo levers, the bars are wrapped with bennetto 'cello' tape. the rear hub is a flip/flop fixed and freewheel compatible, the rear rim is a campagnolo mockva '80, it has ritchey cyclocross tires. the gearing is 38X16, the crank is 170 mm, i ride with standard pedals.
This rig is similar to the bike I raced my first cross race in 03. It was a schwinn letour with 27 inch IRD knobbies. Just a coaster brake. It was real scary.
scary is good!