Coincidentally, I'm currently working on a project to make IPython an (even) better tool for instruction and writing interactive 'textbooks', like what OP has done.
If anybody on here is an instructor who has a similar workflow, or is interested in trying something like this out, please drop me a line. We're in the middle of researching the most important areas for improvement, and we'd love to hear your feedback!
(EDIT: Email my username at Google's email service.)