I've given the BookDesigner a go to generate LRF files and the results were impressive but I had the following major issues which stop me from using it. I'm mostly converting HTML either from Gutenberg or marked up text using GutenMark, which generates HTML. When loading a HTML document that has images, the images do not load. Also the biggest problem is that pagination does not work properly, sometimes page breaks just appear in the middle of paragraphs - is there anyway to switch pagination off?
A good example of the HTML with images that uses CSS from Gutenberg is
http://www.gutenberg.org/files/19420/19420-h.zip