This appears to be working for the artwork.
If installed through RetroPie, first create symbolic link: sudo ln -s /opt/retropie/supplementary/skyscraper/Skyscraper /usr/local/bin/Skyscraper
Command line example for SNES in the USA region with use with EmulationStation: Skyscraper -p snes -s screenscraper -u username:password --unattend --nohints --region us
Command line options
/retropie/configs/all/skyscraper/config.ini
Config.ini options
Config.ini region options
EDIT: After the artwork is downloaded i was able to generate gamelist.xml.