Google 73 mm reach, nutted calipers. Velo Orange had Tektro make some. You might be able to put some nutted calipers together yourself. The alternative is to get 73mm reach recesed nut calipers and carefully drill out the back of the holes on the frame to fit recessed nuts. I've done this and it works fine; just use a lubricant on the fork crown as the steel can be very hard.

http://velo-orange.blogspot.com/2009...ed-brakes.html