iusethis.com redirects URLs like
http://osx.iusethis.com/app/download/appname to download links, and you could
curl MacUpdate pages for direct download links. Are there any more complete or reliable sources for download links?
How could you automate extracting different types of archives or running installers? DropZone comes with a script that accepts dmg or zip files as input and moves application bundles inside them to
/Applications/. Does anyone know a similar script that would work with installers or more file types?