Server Deployment of Economist.com
They have 2 Varnish servers, 10 web servers and 4 database nodes (2 master, 2 slave)

Their workflow is Trunk -> Stage -> Live, from bzr.

They are fully Drupal for a month or so, now.

See The Economist: An Informal Technical Case Study session video from DrupalCon London for more information on their processes.