Designed and built this portable printer some time ago.
built with printed parts and extruded aluminum angles and briefcase from the local hardware store.
http://www.printmaster3d.com/383976112
Impresive! Does it work OK?
It was a bit noisy but did ok at low speeds. Have built another more sturdy portable printer (http://www.printmaster3d.com/383976111) that did very well.