The as-yet-unsolved slaying of fashion writer Christa Worthington in Cape Cod has made for frequent newspaper and magazine stories on both sides of the Atlantic. Now executive editor Charles Conrad at Broadway has bought world rights to a book by novelist Maria Flook, a Cape Cod neighbor of the slain woman, from agent Gail Hochman at Brandt & Hochman, and hopes to publish in fall 2003.... Melody Guy at Villard's Strivers Row imprint has signed for a further two novels by African-American writer Travis Hunter, whose books are perennial Essence magazine bestsellers; she bought North American rights from agent Elaine Koster .... No fewer than seven titles by the prolific Meggin Cabot were signed for Avon by Carrie Ferron: three historical romances under the Patricia Cabot byline and three contemporary romances under her own--plus a comic novel told in e-mails, The Boy Next Door. The seller of world rights in all this was Laura Langlie.