I randomly ran into a book of short stories named Amor and Psycho. Apparently the short story "She Bites" is about a woman slowly transforming into a dog while her boyfriend builds a dog house. I don't know how good it is or anything like that, but I was intrigued. If anyone wants to buy the ebook, here's a link to the amazon listing.
http://www.amazon.com/Psycho-Vintage.../dp/0307741478
EDIT: Actually, I was able to find a PDF of this... not worth anyone's time. It's not really a transformation, maybe mental...but pretty bad.