I found a 2014 email from Thijs indicating that Rackspace had contacted him about a system migration, and that the new IP address would be 162.209.126.109. That's still a rackspace IP, but isn't pingable.
I also found a 2011 email where Colin mentioned "our lovely contact at Rackspace".
Perhaps Thijs or Colin either have an update in email, or know who to contact?