House Flipper to the Stars: MGM Honcho a 'Miserly' Tightwad

The co-CEO of MGM Studios is a bitter cheapskate ... who's trying to sue his way into a "free remodel" of the Beverly Hills mansion he bought from an L.A. real estate tycoon ... this according to legal docs obtained by TMZ.

Sandy Gallin -- who's flipped and sold homes to Sinatra, Kenny G and Mark Burnett -- has filed a response in his bitter legal war with MGM honcho Roger Birnbaum. In the docs, Gallin claims Roger only filed a lawsuit against him because he's embarrassed that the home he bought from Gallin in 2007 for $16.5 mil has gone down in value.

TMZ broke the story, Birnbaum claims the home leaks like a sieve ... and he believes Gallin should have to pay for all of the repairs and related costs -- including a new roof. He's demanding $500k.

But Gallin shoots back -- saying, "[Birnbaum] is motivated by his well-known miserly and parsimonious behavior in his efforts to avoid paying for the roofing remodel himself, which he believes will increase the value of the property that is , embarrassingly to Birnbaum, worth less than what he paid for it."