Upload & Sell: Off
I don't intend to discourage the OP. I'm just sharing info I've gathered from a friend who has gone down this route, and who also has friends who have gone down this route, too.
Note, I'm referring to commercial photographers with solid reputations, and some big clients.
From what he told me, typically, the photographer seeking a book deal usually invests more of his own money into the book than the publisher does. Ultimately, these books, regardless of how stellar the content, are viewed as coffee table books, and generally don't receive the marketing from the publisher, nor the acknowledgement from book critics that they might deserve, and are typically seen as a loss in profits.
I also have friends in publishing that have told me numerous times that the agents and critics are very 'friendly', and more often than not, those NY Times bestsellers are the result of a good agent with impeccable powers of persuasion, if you catch my drift. I just don't see that sort of effort going into marketing a photo book, unless it's the photographer doing the legwork.
I'm sure this isn't true for all photo books, especially historically significant ones like Penn, Avedon, Adams, etc., but generally speaking, consider how many photo books you've come across in a bookstore: where they are on display, how many have clearance stickers, and how popular they really are.
See what I mean?
They generally don't make money, and it's tough to get a publisher to run it.
I think you're better off investing a few hundred dollars at blurb.com, and running off a dozen copies or so. I know photographers that successfully run-off books through this service, and successfully sell them, independently. Try that first. If they are a success, pitch that accomplishment to a publisher.
Don't want to see you get burned is all...