It extends to deployment. Off top of my head, the script that you have to write to trivially deploy with virtualenv is something like:

    virtualenv --no-site-packages -p$PYTHON $workdir
    "$workdir/bin/activate"
    (cd $my-package-dir && python setup.py)
    "$workdir/bin/deactivate"
    virtualenv --relocatable "$workdir"
    fpm -s dir -t deb -n "$package" -p "$package.deb" -d <system dependencies> ...

And you have a deb that you can just scp anywhere and it'll just work.