John,
About the engine, Playboy will probably opt to go with the Williams International FJ-44, which powers the smallest Cessna Citation Business Jet. The engine would be around $400,000. A professionally rebuilt GE J-85 would only cost around $85,000 (as used in the smallest Lear Jet, T-38, and ViperJet out of Pasco, Wa. www.viperjet.com) but it is a fuel hog and old technology. I'm sure Hugh Hefner would want the airplane to have the latest and greatest, regardless of the cost.