The cost of color books is significantly more than black and white books. When you select the color printing ("Full color pages") option in the publishing wizard, the cost is $0.20 for every page in the book, not just the pages with color.So a 200 page book would be $40. Nope, I don't think so. That means either Lulu is out, or the color photos are out. (Black and white seems to be 2 cents a page, plus $4.50 for binding. Less than $10 for the book's direct printing costs. But it would be so bland...)
Check my previous post about the content of Playing With Math: Stories from Math Circles, Homeschoolers, and the Internet. Over twenty authors have contributed, and it's looking good.
The recommendations so far are really helpful, and remind me that I have one more question: Do any of these places use recycled paper?