J.M.
I've been looking for something like this as well. I'm not much of a yard sale person so I'd love to find a way for me to unload all the unworn kids clothes I have sitting in my closet too.
I don't know of a store front but if you're looking to just get rid of the items I have used freecycle before. I'm guessing that might not be what you're looking for.
I'd be interested in what you find out.