Shift Workspaces has doubled down on what it believes is the future of office, opening its second shared office and co-working campus in central Denver. The Denver-based shared workspace provider unveiled the 22,000-square-foot building last week, its 87 private offices at 1001 Bannock St. already about 50 percent leased and expected to be full by the end of the year, Shift founder and CEO Grant Barnhill said. “Traditional office space in a lot of ways is really dead,” Barnhill said during a tour late last week.