A waterfront spec home developed by Gamma Construction at 9530 W Broadview Dr., Bay Harbor Islands has hit the market for $25 million. One of the few new construction homes of its kind on the South Florida market, the total 9,000-square-foot estate is listed by Jill Hertzberg, Jill Eber and Danny Hertzberg of The Jills Zeder Group, affiliated with Coldwell Banker Realty.