That's interesting, I've heard that CS5 is pretty disappointing in that regard. We probably won't upgrade in a while anyway as we'll have to do it company-wide.
We use Indesign to lay out the paper books, and the last few revisions only exist as Indesign documents and PDFs, so we're pretty much stuck with it. The production path I've devised actually works pretty well for us, usually producing an epub from a press indd takes about 15-30 minutes. I'm thinking about polishing and translating the guide for general consumption as well. It might be useful for someone, and it's in everybody's best interest that people know how to produce quality epubs
