The first edition of the book is out!
Make Your Own Mandelbrot [Kindle Edition]
I could have gone on forever fixing and tweaking to the nth degree, so I pulled the trigger as soon as I thought it was good enough.
Please do feed back your opinions, corrections, requests for further explanations. If you're particularly helpful I might give you a copy of the updated edition for free!
I have been disappointed with the whole epub/mobi formats and the quality and varitation in rendering across devices. Google bookshop does allow PDFs which you have much greater control over .. so I'm lookign forward to doing some nicer design for it.