My coauthor recently sent an email to me and our agent letting us know that he was backing out of the book proposal. He cited a lack of time and I completely understand his reasons, but it does mean that I need to rethink things. To be quite blunt, I don't have the breadth of knowledge to write what we were pitching, so I had to blunt about that. Instead, I started working on a proposal that better reflects my skill set and still would be of benefit to the community.
For whatever reason, it appears that publishers seem to be hungry for books right now. Through my agent, I was approached about two different deals. One is for a Perl book that, for various reasons, can't quite fit what the publisher is looking for. I asked for clarification on some of their points, but haven't heard back.
The other Perl book was for something that I know nothing about. I was sorely tempted, but I think it wouldn't be fair to the Perl community for me to follow the Make Sh*t Up route. So I hit that editor with a counter-proposal and she actually liked it! Now, I just need to finish it and add some tweaks to fit their needs. Unfortunately, at over 500 lines of POD, I had to stop and rethink the structure. It's a pretty ambitious proposal and has soooo many ways to go wrong.