One of Penguin Putnam's star authors, Patricia Cornwell, helped silence speculation about a post-Phyllis Grann flight of top sellers by signing up for two new Kay Scarpetta novels with president Susan Petersen Kennedy. The deal, which was in addition to two Scarpetta novels and one non-Scarpetta one still under contract, was made with agent Esther Newberg at ICM, and the author commented: "Putnam has done a wonderful job for me. Why would I want to be published anywhere else?"... We reported here December 10 on the sale of a book about Dante as a guide for modern living, believed to be a first; not so, says former Doubleday editor Harriet Rubin, now a full-time author, who had earlier sold a proposal called In Dante's Path for a "significant" six figures to Alice Mayhew and David Rosenthal at S&S; the deal, for North American English rights, was made by agent Glen Hartley at Writers Representatives, and planned pub date is late this year.