I have begun to implement reading metadata from the comic file, but only a first workflow. I think I can include this relatively easy.
Expanding that to read more than the standart calibre metadata would be possible. What needed to be done in addition is making an option menu, where the user could enter the names of his custom columns for that extra infos and just expanding the function that maps comictagger metadata to calibre metadata with the additional fields.
I don't know if I myself will do this. I haven't worked with custom columns in the code yet and it would be some work to write the gui and map all the additional infos.
The project is on
github (the version there is a little bit different to the live plugin, since I have tinkered with it since the last real version). I develop the read feature currently in the " read_cix_metadata" branch.