Can't create subtheme using drush

using Drush 5.8 on OSX as per configuration in post here:
http://realityloop.com/blog/2012/07/03/nginx-mariadb-php-aegir-mac-os-x-...

Ah, that makes sense, unfortunately I've tried all the iterations I can think of and I'm still getting the error..

brian at rl: ~/Sites/drupal-7.18/sites/realityloop.com
→ ls -la
total 216
dr-xr-xr-x  10 brian  staff    340 23 Dec 13:48 .
drwxr-xr-x   8 brian  staff    272 23 Dec 12:07 ..
-r--r-----   1 brian  staff  99847 23 Dec 13:51 drushrc.php
drwxrwx---  11 brian  _www     374 24 Dec 10:39 files
drwxrwsr-x   5 brian  staff    170 23 Dec 12:15 libraries
-rw-r--r--   1 brian  staff    138 23 Dec 13:50 local.settings.php
drwxrwsr-x   4 brian  staff    136 23 Dec 12:32 modules
drwxrwx---   4 brian  _www     136 23 Dec 12:07 private
-r--r-----   1 brian  _www    3150 23 Dec 13:51 settings.php
drwxrwsr-x   4 brian  staff    136 24 Dec 10:42 themes

brian at rl: ~/Sites/drupal-7.18/sites/realityloop.com
→ drush omega-subtheme "Realityloop" --destination="sites/realityloop.com"
The destination is invalid.                   [error]
brian at rl: ~/Sites/drupal-7.18/sites/realityloop.com
→ drush omega-subtheme "Realityloop" --destination="sites/realityloop.com/themes/"
The destination is invalid.                   [error]

brian at rl: ~/Sites/drupal-7.18/sites/realityloop.com
→ cd themes 
brian at rl: ~/Sites/drupal-7.18/sites/realityloop.com/themes
→ ls -la
total 0
drwxrwsr-x   4 brian  staff  136 24 Dec 10:42 .
dr-xr-xr-x  10 brian  staff  340 23 Dec 13:48 ..
drwxrwsr-x   7 brian  staff  238 23 Dec 12:16 fusion
drwxrwxr-x  23 brian  staff  782 23 Dec 14:17 omega

have drush cc drush, drush cc all, and still getting the same errors.

content of my sites.php file

<?php 
/**
 * @file
 * Configuration file for Drupal's multi-site directory aliasing feature.
 *
 * Drupal searches for an appropriate configuration directory based on the
 * website's hostname and pathname. A detailed description of the rules for
 * discovering the configuration directory can be found in the comment
 * documentation in 'sites/default/default.settings.php'.
 *
 * This file allows you to define a set of aliases that map hostnames and
 * pathnames to configuration directories. These aliases are loaded prior to
 * scanning for directories, and they are exempt from the normal discovery
 * rules. The aliases are defined in an associative array named $sites, which
 * should look similar to the following:
 *
 * $sites = array(
 *   'devexample.com' => 'example.com',
 *   'localhost.example' => 'example.com',
 * );
 *
 * The above array will cause Drupal to look for a directory named
 * "example.com" in the sites directory whenever a request comes from
 * "example.com", "devexample.com", or "localhost/example". That is useful
 * on development servers, where the domain name may not be the same as the
 * domain of the live server. Since Drupal stores file paths into the database
 * (files, system table, etc.) this will ensure the paths are correct while
 * accessed on development servers.
 *
 * To use this file, copy and rename it such that its path plus filename is
 * 'sites/sites.php'. If you don't need to use multi-site directory aliasing,
 * then you can safely ignore this file, and Drupal will ignore it too.
 */

/**
 * Multi-site directory aliasing:
 *
 * Edit the lines below to define directory aliases. Remove the leading hash
 * signs to enable.
 */
$sites = array (
  'realityloop.ld' => 'realityloop.com',
);