Pacific Realty Associates is moving forward to build an office campus in El Dorado Hills that could possibly house 2,500 workers. Portland, Ore.-based Pacific Realty, also known as PacTrust, hopes to start construction on the first two buildings this spring, with plans to build as much as 800,000 square feet for offices and manufacturing. PacTrust bought the 100-acre property in 2004, but had not detailed its plans until recently. PacTrust wants to develop 50,000- to 100,000-square-foot buildings, a size that is not widely available in El Dorado Hills. PacTrust has a couple of possible tenants, including two tech companies that could create a combined 300 jobs.