More notes-to-self. Not all relevent to this build, but relevant to troubleshooting issues found in testing this build etc.
Try to use a more forgiving pat-cache method. Following example from http://askubuntu.com/questions/53443/how-do-i-ignore-a-proxy-if-not-available to use my local apt-cache if available, but with a fall-through to normal repos if not
note about how apt-cache init works
Use the recommended and autodiscoverable hashicorp/precise64 when local