CHICAGO - Two private U.S. companies have designs on building the first luxury recreational vehicle that could withstand nuclear radiation. Parliament Coach Corp., a privately held company in Clearwater, Florida, which converts Prevost buses into high-end RVs, has partnered with Homeland Defense Vehicles to offer consumers a luxury motor coach that can protect occupants against nuclear radiation from dirty bombs as well as biological and chemical attacks. The idea is to offer the option on the pricey vehicles to consumers worried about terror attacks, officials for both companies said Tuesday. "Many people enjoy the RV lifestyle, but we also live...