At press time, New York-headquartered Chelsea Pictures was about to open a Los Angeles office. Allison Amon has been named executive producer and though she will work out of the L.A. digs, she will share responsibility for Chelsea’s overall body of work with the company’s New York-based president, Steve Wax. Meanwhile, executive producer Maddi Carlton is leaving the shop for another opportunity to be announced shortly…. Creative Film Management International has signed director Nick Cassavetes in what marks the first commercial representation for the feature actor/director…..Who’s the new director set to join Dektor Film, Hollywood?….Craig Ferber-who left his account executive post last year at TBWA/Chiat/Day, New York, to put together a directorial reel-has signed with Right Brain Films, the Los Angeles-based shop headed by exec. producer Stuart Wilson….Don Sebesky, who recently signed with Montclair, N.J.-based music and sound design house Mess Hall for spots, took home a Grammy during the recent award show which was held on Feb. 24. Sebesky’s work on the track "Waltz For Debby" from "I Remember Bill-A Tribute to Bill Evans" was honored in the Best Instrumental Arrangement category…