THE musical Singin' in the Rain has been a turning point in the career of Wayne Scott Kermond.  Kermond has been performing in musicals, cabaret and film work since he was a boy but since Singin' in the Rain, he has come to the attention of producers.     "They can see me as a sellable product in the sense of other shows that come along.  People now know Wayne Scott Kermond is a good performer and can help put bums on seats," says Kermond.     "Todd McKenney (his Singin' in the Rain co-star) proved that with The Boy from Oz. That's certainly launched him in a big way."     Kermond's character, Cosmo Brown, is a lovable loser.     He doesn't get the girl but he gets to run up the wall and gets the funny lines.  In his stand-out scene Make 'Em Laugh, Kermond does plenty of somersaults.     "I've been performing acrobatics since I was about six.  My parents are performers as well.  My background is vaudeville, slapstick and comedy," he says.     "I'm a fourth-generation performer. My family worked in the Tivoli and Sorlies (travelling vaudeville tent show). They were great tumblers and acrobats."     Kermond is performing in Singin' in the Rain, with his wife Katie as a member of the ensemble and his son Alexander as the young Cosmo Brown.     Kermond's first professional role was in Gypsy when he was 11.  He did other commercial work and performed in pantomimes with his mother and father.  Then at age 17 in 1982, he scored his first Australian touring musical in the role of the smallest man in the world, Tom Thumb, in Barnum.     Kermond says his career is not hampered by his lack of centimetres.     "I think being small has enhanced my career," he says.     "It's worked for me now with Cosmo Brown.  I would look pretty silly if I was taller than Todd.     "What I lose in height I make up for in stature and energy.  All the roles I play -- West Side Story, A Chorus Line -- they've all been energetic and feisty."     "I've always played character roles.  I think they're interesting and funny.  I would like to play the romantic lead but I don't think I'm really romantic-lead material, to be honest with you.  I always find the character roles more interesting to play."     Kermond produced and starred in Jive Junkies, which toured Australia and went to the Edinburgh Fringe.  He has also had roles in TV's The Shiralee, The Heroes and Kings in Grass Castles and in musicals West Side Story, A Chorus Line and Chicago.