One of the nice things about being a programmer is that when I don't find what I need, I can just write it myself.
Here are a couple of the projects that I wrote while working on my novel.
I do my writing in Emacs, so my files can be easily tracked with source code control.
I needed a way to spell check these and to construct an ePub formatted book from the text files.
After I found some english dictionary files at http://wordlist.sourceforge.net I was able to write a simple spell check program.
The actual construction of the ePub is written in Perl. This reads the simple-formatted text files and converts them to HTML, and then generates the table of contents and package everything in an ePub zip file.