alphabetically order role drop-down selection in dashboard

The site I’m working on will have a very large number of unique user roles via a members plugin. Because of that, I’d like to have the Role drop-down selection on the Add New User page to display roles alphabetically, rather than descending order of creation.

Is there any way to do this?

Almost the same approach One Trick Pony has chosen, but I am using translated names and uasort() (to preserve the keys):

add_filter( 'editable_roles', 't5_sort_editable_roles' );

/**
 * Array of roles.
 *
 * @wp-hook editable_roles
 * @param   array $roles
 * @return  array
 */
function t5_sort_editable_roles( $roles )
{
    uasort( $roles, 't5_uasort_editable_roles' );
    return $roles;
}
/**
 * Compare translated role names.
 *
 * @param  array $a First role
 * @param  array $b Second role
 * @return number
 */
function t5_uasort_editable_roles( $a, $b )
{
    return strcasecmp(
        translate_user_role( $a['name'] ),
        translate_user_role( $b['name'] )
    );
}

As a plugin on GitHub.