One needs to determine whether this is a first prototype with limited functionality, which requires some global testing, or whether it refers to the last iteration before deployment.
You must select the appropriate deployment model by balancing your needs for customization and control against the TCO and TTV that your business requires.
Capistrano is used widely among Ruby and Rails developers to deploy code to servers, but it's an excellent choice for automating most distributed systems administration tasks.
The Capistrano deployment gem includes a task, cap deploy: web: disable, that puts a maintenance page on the site informing users that the site is down for maintenance.
A Ruby Gem called Capistrano manages these deployments in a way that allows for centralized control of multiple servers and easy rollback if problems are encountered.
The recent announcement Jamis Buck is ending development of Capistrano has left many wondering the future of this deployment tool. The release of Vlad 1.3 gives others hope as an alternative.