These days, Jim Ellis and the realty firm he heads, Ellis Partners, seem to be everywhere, key players in the most robust development markets of the Bay Area. Jack London Square in Oakland, which is undergoing a $400 million revival and renovation; The Pruneyard complex in Campbell; Town & Country Village in Palo Alto; and a big North San Jose office project where tech titan Apple has just leased a huge chunk of space, are all projects being guided by Ellis Partners, whose principal executives are Jim Ellis and his sister, Melinda Ellis Evers.