In the Plucker source code there is a program called “explode”. When you run it on a Plucker ebook, it “explodes” the book into HTML and images. This isn't easy to get for Windows, but it may be part of a Plucker viewer for Windows (that is also hard to get). The links to binaries no longer works, but see
Plucker -> Reader.
It seems a bit strange to use Sunrise to "pluck" web pages and then explode the result to recreate HTML, however this isn't the original HTML but a simplified Plucker variant. If you can get this to work, then Calibre can convert to ePub for Stanza, or perhaps the plucker HTML (if it is a single file - I'm not sure if it is or not) will be readable directly by Stanza. If someone has a Python version of plucker's explode then plucker could probably easily be added to Calibre's any2epub.