there might be some gaps (let me know) but you can actually pipe the output to another program.

for instance here's how you'd download all the unread blog posts by combining blogtato and wget:

blog .unread read | wget \ --recursive --level=1 \ --page-requisites \ --convert-links \ --adjust-extension \ --no-parent \ --directory-prefix="$HOME/offline-posts" \ --input-file=-