Tax breaks intended to pull businesses into economically weak areas could be extended to Miami-Dade developers of high end condos, and the county could get a cut. A plan recommended by Mayor Carlos Alvarez and endorsed by county commissioners would move the boundaries of the county Enterprise Zone, and as a result would offer up to $47 million in sales tax rebates to developers of six luxury condo projects. Beneficiaries would include Icon Brickell, a Miami River-front tower built by Jorge Pérez’s Related Group, and the massive Biscayne Landing project on the Intracoastal Waterway in North Miami. Quantum on the Bay, built by Pedro Martin’s Terra Group, is already occupied by condo owners who paid as much as $500,000. Just two of the six projects promise to build homes that meet the county’s definition of affordable.