audible.com -- chances are slim that a publisher will negotiate with you. If the book is self-published -- for example, it's offered via Createspace -- the author retains the rights and it should be easier to contact and negotiate.
What's a novice audiobook producer supposed to do? One way to break into the audiobook production world and acquire experience is to record public domain books (and there are a few centuries of good material available to download). (We just finished listening to Leo T.'s Anna Karenina and wow, that was amazing!!) Another possibility is to sign up with the Audiobook Creation Exchange (ACX), sponsored by audible.com. That system pairs audiobook producers with established publishers and authors. We've prepared a free sample voice-over release to use with your narrators. You can read more about it, here.