Restoring is another 6 lines of bash:

    s3cmd --config ~/.s3cfg get s3://BUCKET/database_$1.sql.gz
    gunzip database_$1.sql.gz
    sudo -u postgres dropdb DBNAME
    sudo -u postgres createdb -O DBUSER DBNAME
    sudo -u postgres psql DBNAME < database_$1.sql
    rm database_$1.sql

But I suppose being database agnostic would be handy - it would make switching from mysql to postgres easier.