Okay... so I just noticed this thread....
I was, at one point, contemplating putting in a little button, probably next to the print button, that would save the story in epub format.
The Author could set the flag in the story properties to control it; like the anonymous posts thing. Doesn't stop scraping the HTML and creating one that way, but would block the "easy" access to it.
I'd just need to re-dig up my links on the epub format (really, it's just a ZIP container and some XML files, but a specific layout... kinda like odt/docx

), and do some basic testing with a few stories to come up with some working CSS layout file.
I'll ponder it a bit more and see if I can come up with something sane.
-J