The Ithacus (diagram.)
"Douglas also proposed a military VTVL SSTO for transporting troops and cargo -- the Ithacus. The Ithacus plan was apparently inspired by general Wallace M. Greene, who proposed a rapid-strike batallion of 1200 soldiers. These 'rocket commandos' would have been deployed by an intercontinental rocket so the need for overseas US Army bases might be greatly reduced. The gigantic 6400-tonne Ithacus Sr. was supposed to serve this strategic need."