John H. Ellwood, founder of an eponymous consulting firm, has retired and sold the last remaining shares of the company to its employee stock ownership plan. The firm will now operate as Ellwood Associates. Russell W. Hill, formerly the firm's president, was named chairman and CEO, replacing Mr. Ellwood. Susan B. Toth, director of support services, was named president and COO, a new position. Daniel R. George was named CIO, a new position, and will remain director of consulting.