Ok, I just can't let an unrearched question just lie there. Here is what I learned about the abundance of hams hanging from the ceilings in so many stores here:

"Practicing Jews do not eat pork or meat from the pig. The Christian Spaniards knew this and therefore hung ham and other pork products visibly in their homes. This could quickly identify them as not being Jewish to the passerby. Jamón ibérico hung from the ceiling of an establishment could serve as a warning that Jews were not welcome, as well."