Ask HN: Any interest in a CakePHP book?

I've recently read about several people who have been successful in selling their ebooks. Following successful entrepreneur's advice, I'm looking for a topic I know well enough and that has a big enough target audience. I arrived at the idea of making a CakePHP book.

When I was learning CakePHP myself, I suffered because all the available books were old and the framework has changed sufficiently to make them useless as a learning tool. I've found the following pros and cons:

PROS:

- PHP remains one of the most used languages for the web, and CakePHP is one of the most popular PHP frameworks.

- All existing books are really outdated.

- It's a topic I know well, and know common questions people will have when learning it.

CONS:

- Ruby, Python, etc are hipper and probably what more people want to learn.

Would you as a developer be interested in a CakePHP ebook? Any feedback regarding the idea?

Thanks