[AcidWeb]

OK. That make sense. I done that too few times.

To be frank implementing this pipeline to KCC would require tremendous amount of work and I don't see me doing that in the near future.

But I think that entire process can be automated will batch script. You can use Calibre plugins from command line.

Let's look on the process:
De-DRM -> Extracting images -> Embedding metadata -> Converting to EPUB.

De-DRM - Apprentice Alf plugin.
Extracting images - Kindle Unpack plugin. You don't need to compress it as KCC can use raw directory as input.
Embedding metadata - This is only problematic step. Somehow, something need to create XML file in ComicRack format and place it inside image directory.
Converting to EPUB - Command line KCC.

Metadata step can be skipped. You can already set the title using KCC command line option. I think I can add option to set author too if that would help you.