The wealthy visionary behind a downtown Kalamazoo sports and entertainment arena 27 years in the making shared as-yet-unreleased details on the project at an event Thursday. Greenleaf Companies founder and chair William Johnston said the schematic design phase is now complete on the proposed $300 million, 320,000-square-foot Kalamazoo Event Center. His company’s real estate development arm, Catalyst Development Co. LLC, hopes to break ground on the project in November.