Greetings All,
I had previously tried to describe this little part unsuccessfully to both the List and to many seasoned local mechanics. So I suspect that in the US it may in fact have been as uncommon as 650B bikes were.
Finally with camera and computer making beautiful music together, I can offer you clear photos on this webpage:
http://community-2.webtv.net/
Anyone seen one of these racsals floating around their shops or old parts boxes? If you have one please do let me know. In fact, I'd be curious to know if anyone has this type of attachment on their own bikes. Definitely designed for bikes intended to be fitted with fenders.
The short brake mounting bolt is essentially the same one used to hold Mafac center-pull arms on their pivots. The entire caliper can actually be removed using a thin 12 mm open end wrench... and without effecting the still firmly anchored fender.
Perhaps I'm just overly impressed with shiny little bits of useful metal, but I think they are a wonderful design.
Bob Hanson, Albuquerque, New Mexico, USA