Specific Case:
Site to parse is not available at port 80 so port must be appended to web
address when setting up the copy. Some links that I would like to follow on
the site however are absolute and then fail as it tries to go out over port 80
then. I'd like to be able to append the port to those absolute URL's. I did
not see any option that existed either through the GUI or command line, even
the expert (Do Not Use) options that might accomplish this.

Simple option:
Separate port info from url's to parse and add option to append that port
anytime it sees an absolute URL without it.

A more flexible option (but not sure how useful):
Implement regex search/replace filters on parsed URL's to be applied before
attempting download. To simplify regex's add option to execute the regex
against the domain, path, or both. You've already got that done so no need to
overcomplicate the regex's.