Josh Flagg is cashing in on Miami heat ... listing his $10 million estate directly across from The Beckham's $72.3 million compound ... TMZ has learned. The "Million Dollar Listing" star listed the place ten days ago ... a Mediterranean-style estate he gutted and rebuilt with BuiltIN Studio's Gary Eisner . The 4,000 square foot home on a 10,000 square foot lot features 4 beds, 5 baths, vaulted ceilings, custom steel doors, serious security, and a detached pool house with a sauna and cold plunge.