Is there a means to pass some php.ini settings to the drush command?
First, remember that php.ini for Command Line Interface is separate and has nothing to do with php.ini your webserver is using. To find where that file is, follow this question on SO as this is not really on-topic on Drupal Answers.

If you want to set some php.ini values in drushrc.php, you need to use ini_set() PHP function. Just remember that not all values are changeable like that, only the ones with PHP_INI_USER (or PHP_INI_ALL, of course) on this list.