Boeing is leasing the single largest available Everett-area structure, the former Intermec Corp. headquarters, to respond to its need for working space as production rises. The 312,000-square-foot building, in a wooded setting less than a mile north of the Boeing Everett plant, offers a significant amount of single-floor space, suitable for office work or light manufacturing, said Matthew Henn , senior vice president for Kidder Matthews , a commercial real estate broker.