Thank you. I've been downloading books from Mobileread for a while, but have mainly been sticking to the BBEB format until now. I'll make sure to check out Jellby's books also.
And I'm already looking at this book in Sigil, actually. Great editor. I might even make an epub version of a book myself if I can think of something appropriate, but you've already made the one illustrated book I was most interested in.