I just released the first version of Teleport, a Ruby gem that makes it easy to setup Ubuntu servers. It’s conceptually based on work that I first did at Urbanspoon, then radically updated for Cubeduel and then Dwellable. Details here:

https://github.com/rglabs/teleport

Here’s a sample Telfile:

user "admin"
ruby "1.9.2"
apt "deb http://downloads-distro.mongodb.org/repo/ubuntu-upstart dist 10gen", :key => "7F0CAB10"
role :app, :packages => [:memcached]
role :db, :packages => [:mongodb-10gen]
server "server_app1", :role => :app
server "server_db1", :role => :db
packages [:atop, :emacs, :gcc]