Here's an out-of-the-box suggestion... the Gilles Berthoud Marie Blanque (ss rails) or Agnel (ti rails) measures 157mm wide and 248mm long. After a recent saddle search that yielded disappointing results I decided to take a totally different direction by purchasing a leather saddle (Gilles Berthoud Aravis). I had always avoided leather saddles because I just couldn't wrap my head around the concept and thought it could never be comfortable. Plus, they're bloody expensive! Long-story short, the Gilles Berthoud is hand's down the best saddle I've ever ridden and worth every penny. I admit they may not be for everyone, but it's worth considering.