Howard Ecker has run Howard Ecker + Company, an international commercial tenant representation and brokerage firm, for 40 years. His firm does a lot with a little. A team of fewer than 30 employees — including his daughters, Valentine and Kinzie — has managed to maintain a client list that includes BDO USA, Ameritech and Sam Zell’s Equity Residential. Andrea Miller left a career as a Wall Street bond trader to begin her own commercial real estate brokerage last year, and now has a team of four.