One of these writers was published in hardcover by Philomel Books. She wrote and illustrated a book about a young Masai boy who is leading his herd of goats home after a day out on the plains of Africa. Interesting thing about this book (and something the author learned while attending conferences and weekend-long writing seminars with SCBWI) was teaching young readers about ethnicity. She created a simple, lyrical text in both Swahili and English. As the boy heads home, he passes animals of the African plains, and says good-night to each - thus, the reader learns the Swahili word for hyena, rhinoceros, etc.
Anyway, my point is she harvested a lot of great info over the years by being a member of SCBWI...and it was during one of the many weekend-long seminars that she got to work with an editor and that's when her book really took shape.
You didn't state what type of children's book you have in mind, or for what age bracket. Or if you have a format in mind, say, a glow book, or a hard cardboard die cut, etc., for young readers.
What I learned from our own venture into this is that publishers of children's book sometimes buy copyrights, and they spend a great deal of money obtaining these rights. What they end up with is a vast library, with major characters they can use in different formats, so of course, they're going to be thinking about how to use those characters they've paid for. Do you have a neat idea - format and storywise - that could fit into something like that? They also work with "packagers," or what I term "think tanks" - companies that focus on revolutionary ideas in terms of packaging/design. For instance, a "pin book," in the shape of an apple or a bell, that the child can read and then wear as a pin.
The following is a Web page with a bit of info about pop-up books & their designs/designers: http://www.library.unt.edu/rarebooks/exhibits/popup2/present.htm.
Do you have a "patentable" idea for a children's book? If so, a packager might be interested in the project - but you need to thoroughly research in terms of technology and application the idea you come up with before they'd work with an outside creative person. A few years back Intervision Inc. in Santa Monica was one, as was White Heat in Santa Fe, New Mexico. These packagers produce a "model" for the publisher, and then the books are most often produced outside of the country, then shipped to the publisher for distribution.
Something you might want to do if possible is attend a book show. One to maybe consider is BookExpo America. Check out the Web site at: www.bookexpoamerica.com.
Lots of exhibitors at this type of thing - publishers and wholesalers, I suspect - and more info under one roof than you could gather quickly on your own (plus inspiration, yes?).
And if your idea is to write the next Harry Potter series, then I've just wasted your time with my too-long post! Just thought I'd share what I learned.... Good luck!
If you want to take a look at it and let me know what you think, as far as usability, and what kind of market it might work for, that would be great.