Here is an easy way to build an exactly similar ubuntu installation on another computer.
$ dpkg --get-selections >my_pakages
on the machine
that you want to clone. Install a clean copy of Ubuntu on the target
machine. Copy the file my_packages to the target machine.
Run the following command on the target machine.
$ sudo dpkg --set-selections < ./package_names
$ sudo apt-get -u dselect-upgrade