Three top Cliff Freeman executives have split the agency to start their own shop. EVP-director of new-business development Charles Rosen, chief strategist Doug Cameron and VP-associate creative director Jason Gaboriau are opening a new boutique called Amalgamated in Manhattan's financial district. ... The execs behind Backyard Productions have joined with their programming/production partners to form a new commercials production shop, Seed. Backyard principals Blair Stribley and Roy Skillicorn are working with Science+Fiction founders Steve Mendelson and Kevin Townsend in the new production studio, which will focus on developing young directorial talent in commercials and the programming realm. Mendelson, a TV producer, and Townsend, former ILM Commercials VP-GM, launched Science+Fiction two years ago to develop branded programming and interactive TV. ... Seed's initial roster includes Michael Chaves, a recent Pasadena Art Center grad, and Jim Byrkit, who is currently repped in Canada by Mad Films. ... In London, Mother's Jim Thornton and Paul Shearer of Wieden + Kennedy/Amsterdam have been named co-executive creative directors at Leo Burnett's London office. As co-ECDs, the pair succeed Mark Tutssel and Nick Bell, who shared the title in 2001, when the office was among the most successful creative shops in the world, winning three film Gold Lions, including one for the now-classic "Bear" spot for John West salmon. Tutssel departed at the beginning of 2002 to become deputy chief creative officer at Leo Burnett USA, while Bell was named ECD at J. Walter Thompson/London earlier this year.