A bit of a drive from you, but we found a farmers 2nd hand barn in Walenstadt SG, info on this thread (sorry, all the photos have since been moved). He had real old used cow bells, not the shiny tourist ones and prices seemed pretty reasonable (a beautiful one from 1949 was 300.00)
If the OP is interested, I might be in that neck of the country soon to settle a matter, I could pick it up and bring it to Basel when I am next there. Which will probably be next week.