Cross trainers will be your next option after walking shoes for easy walking. Reebok and New Balance have a good selection of walking shoes though.
Try eastbay. Their site has a ton of really cool modern and vintage styles in athletic shoes and apparel. It is also my understanding that they have a wide variety of extended sizes in certain styles and brands. Good luck.
DSW does carry a good variety of athletic shoes - heavier in running, but there are cross-trainers, tennis, etc. Just make sure you get actual athletic shoes versus some of the "fashion athletic" (looks like athletic but doesn't have same technical f...