And no, I'm not kidding. I could make more money flinging hamburgers than writing some of the books I've written. {grin}

Why not self-publish? I know of one person who makes a good bit of money by selling his own books online as PDF files. Certainly, he sells much fewer copies than even a weak O'Reilly title, but his profit margin is almost 100%. And yes, the final product isn't as polished as an O'Reilly book, but who cares? Your audience is used to slogging through man pages and source code. They won't miss the fancy graphics and the cutesy bear-trap icons.