A few online suppliers of dropout adjustment screws for vintage bike restorations :
1. Loose Screws dropout adjusters, 29mm (halfway between the 'long' 35mm and 'short' 25mm campagnolo adjusters). The caps on these are ALMOST like campagnolo, but campy ones are more narrow (get going with that file and brush chroming set!)
2. Velo-Orange, 28mm ('I just gotta be different !!')
http://www.velo-orange.com/
- Don Gillies San Diego, CA, USA
P.S. traditional ones are covered in black oxide or coated in cadmium. These newer ones are chromed or stainless, so they ones are instantly recognizable as replacements.