DETROIT (AP) — Convincing top executives that Detroit is a comeback city where they should hold company meetings and conventions could only be characterized as the most monumental of pitches or the slickest of con jobs. [...] Bill Bohde, senior vice president for sales and marketing at the Detroit Metro Convention & Visitors Bureau, is plowing ahead with a $1.6 million marketing campaign even as the city is trying to become the largest in the U.S.