This Raleigh Single Speed evolved from a Grand Prix raod bike. While not a rat per se, it began with only a frame and front fork. I found a 27 inch Raleigh high flange front rim on ebay, and I purchased another 27 inch low flange front rim. Then I laced a new Strumey-Archer coaster brake into the extra front rim. The triple heron chainwheel came off a raleigh Superbe, and I use a nickeled KMC chain. The handlebars are North Roads with cork grips on a British style stem. The seat is a Brooks Champion Flyer on a microadjustable seatpost.
It has become one of my favorite bikes. It's simple, tough as nails, light, and fast. You can read more about it here. http://xavierthoughts.blogspot.com/2008/04/raleigh-grand-prix-single-speed.html