Let's share our knowledge of retailers (online and/or b&m) who specialize in or offer a good selection of specialty shoe sizes (wide, narrow, large, small). My own personal challenge is finding attractive, comfortable shoes in extra wide. Here are some sites I have found helpful:

zappos.com

shoes.com

shoetrader.com

shoemall.com

endless.com

designershoes.com

What can you add to the list?