If you’ve published through a small press or even self-published, you can still pitch to Barnes and Noble to see if they’re interested in distributing your book into their stores.  Send a copy of your book along with a cover letter stating how you plan to promote the title, what your marketing and publishing plans are, when you plan to publish, and what your credentials are for writing the book.  You can contact your local B&N store for a name and address for the Small Press Division.  It’s worth a try!