Wiki page for reference to ebook creation tools.
This is really cool, thanks for sharing!
Related: Have you heard of or used Leanpub? It has been my plan to use them if I ever write a technical book. They handle payments, formatting, etc so you can just work on your book and be done with it.
Add Leanpub to the list. I’ve known of them since they launched, but…
When you sign up to write a book on Leanpub, we create a Dropbox folder for the book and we email you a sharing request. If you already have a Dropbox account, you get the new folder in your existing Dropbox account. If you don’t already have a Dropbox account, you need to create one. (Dropbox is a fantastic free private file sharing service used by hundreds of thousands of people.)
Kind of a no go for me. 
Fair enough, I forgot about that constraint. 