MARIAN REES doesn't fit into any of the usual stereotypes of a successful television and film producer. Silver-haired, soft-spoken, and gentle, she is one of the few women in charge of her own TV and film production company, which is sometimes referred to as a ``boutique with Tiffany standards.'' Although Marian Rees Associates Inc. is a baby in show biz - born in 1981 - Ms. Rees has produced ``Foxfire'' with Jessica Tandy and Hume Cronyn; ``Just Between Friends,'' starring Elizabeth Taylor and Carol Burnett; ``The Shell Seekers'' starring Angela Lansbury, and other well-received programs.
Her latest production - ``A Son's Promise,'' a fact-based drama about Terry O'Kelley, starring Rick Schroder - airs Monday on ABC (9-11 p.m., check local listings).
The story ``appeared in People magazine,'' Rees explains, ``telling of the 15-year-old who promised his dying mother to keep the family together. He had six younger brothers, but he did it.
``I was so touched when I read this true account, I flew to Georgia to see Terry. When I got there, I discovered I was the 41st producer to have the same idea of wanting the film rights to his story.''
Although Rees was not the first to arrive and did not offer the most money, O'Kelley selected her to produce the film. When asked why, he replied, ``I think she understands.''
Marian Rees does. She has had her share of struggle. Her first job in TV was as a receptionist at NBC. That was 37 years ago, and it was a slow climb to producer's secretary, to assistant, to associate producer.
``Being a woman in a male-dominated industry has slowed my progress,'' she says. ``I've been overlooked, bypassed for promotions, always underpaid, and dismissed when I asked to produce.
In the beginning ``I had to mortgage my home, my life insurance policy, and my car,'' she explains. ``I was nursing self-doubts starting from a failed marriage and a divorce, to a pink slip from my employer after 15 years on the job. When I asked why I was fired, the reply was, `We think you'll be happier elsewhere.'
Was it those self-doubts?
``Most of my life, I've been almost pathologically shy,'' Rees admits. ``I graduated with a degree in sociology from the University of Iowa, and felt this would be my lifework.''
But ``the leading factor in overcoming shyness was my commitment to a project,'' Rees says.
When she believes in a film, like a bulldog chewing a shoe, she just won't let go.