For fun, I decided to try writing a partial post using Apple’s iBooks Author. The application runs on Mac OS X Lion and is available for free. It appears to be derivative of Keynote, which explains Apple’s rapid development of the authoring tool.
There are some limitations, though. I couldn’t embed equations from Word for Mac 2011 without converting them into images. It also only publishes to iBookstore, although you can export to PDF (as below). There are few PDF export options, however, and the metadata and labeling includes Apple logos.
Tearing apart the .iba format via unzip showed a collection of .jpg and .tiff images, a binary color array, and an .xml specification of the project. Fairly simple, but not including the compiled .epub file that iBookstore generally takes.
Total elapsed time: 1 hour (including download/installation). With improvements to the software and with more experience, that should be halved.