See - http://askubuntu.com/questions/36671/how-do-i-pre-install-ubuntu-for-someone-oem-install
which refers (I think) to - https://help.ubuntu.com/community/Ubuntu_OEM_Installer_Overview
also - My work stopped using Ubuntu Mate which showed me a while ago that oem installs exist.
It’s easy to install Ubuntu on a computer for someone else, so that you can customize it for their needs but they can still perform the final basic setup (username, password, language, etc.). This installation is primarily used by shops that clean up a used computer and resell it.
In the live CD/USB, press F4 which gives you the OEM Install (for manufacturers). Click on it and then click on install Ubuntu.
Enter a temporary username, password and machine-name for the customization phase. Install and restart. I used “oem” for both username and password. The machine name I used was “laminar”. I don’t think that any of this particularly matters.
You are now in the customization phase: Do NOT click on the “Prepare for shipping…” icon until you have finished upgrading, doing updates, installing software, removing software, changing wallpapers, etc. You can reboot as many times as you want. After 4 days, I was still in the customization phase on a toshiba netbook.