Unfortunately, Perl is only available if you jump to Illuminated or Premium.
PHP is also WIDELY used on our servers - we can't enable Perl and remove PHP on the Prime Membership, or we'd pretty much destroy the hosting since PHP is what is the driving force behind vBulletin, IPB, MyBB, PHPBB, SMF, Wordpress, Joomla, Mambo, E107, PHPNuke, multiple Radio softwares, multiple shopping cart systems, etc. I'm not saying perl isn't useful, however given PHP's widespread use on the server, there's pretty much no chance we would be able to remove PHP and still run a business.