The makers of the hit television reality show “Jon & Kate Plus 8” are producing a new series that easily could be called “Kody & Meri & Janelle & Robyn Plus 15.” “Sister Wives,” a seven-episode series for the TLC network, is the first reality show that follows a polygamist family. Filmmakers are profiling Kody Brown and his three sister wives, a group of fundamentalist Mormons in Utah (the family does not want to reveal the city they live in). The show, which was introduced at the Television Critics Association summer press tour in Beverly Hills Friday, premieres Sept. 26...