$CFG->themedir Mostly Broken

The themedir configuration option seems to be quite broken from a few perspectives.

In: lib/moodlelib.php, functio get_list_of_themes():

if (!file_exists("$CFG->dirroot/theme/$theme/config.php")) { // bad folder

Should be:
if (!file_exists("$CFG->themedir/theme/$theme/config.php")) { // bad folder

same goes for:

include("$CFG->dirroot/theme/$theme/config.php");
to:
include("$CFG->themedir/$theme/config.php");

In order to use theme/index.php to select a theme from this directory, one would have to change the get_list_of_plugins_line.

As a trivial example in theme/index.php, i'd need to change:

$themes = get_list_of_plugins("theme");

to:
$themes = get_list_of_plugins("local_theme_dir");

Where local_theme_dir would be under my dirroot. This is what i've found skimming the surface. (Configurable theme directory would be quite powerful for me)