I have only heard of the shedding and bathing myths. I can say that I have 2 bulldog breed dogs which have short hair. I do not have any carpet in my home (carpet is gross to me). I shed hair like crazy, my hair, dog hair and dust gather in corners within a few days if I don't sweep. My boyfriends lab recently came to live with us and labs have longer hair than bulldogs. Within a week I noticed TONS of hair gathering and that I had to sweep everyday compared to a few days a week. Maybe the longer hairs are easier to notice than the short hairs and therefor we think longer haired dogs shed more.
As far as bathing goes, my dogs are inside dogs and get baths every other weekend and sometimes more often in the summer or if they go swimming or to the beach. I haven't noticed any type of change in their skin in the 4 years I have had my dogs. My foster dog came to me with MAJOR skin issues, fungus and skin that looked like mange, although it wasn't. When he gets dirty or goes more than a week without a bath he does get itchy but i think it is due to him being very sensitive to things and already having skin problems.
Very interesting post, I'm going to research some of those myths now and start a thread for breed specific myths.
