Exploring variations in the gauge sector of a six-dimensional flavour   model
  We address the question, how general is the gauge sector in extra-dimensional models which explain hierarchies of masses and mixings of quarks, charged leptons and neutrinos in terms of a single family of multidimensional fermions. We give qualitative arguments that though there are a plethora of possible variations, they do not result in drastical changes of phenomenology. 
Jean-Marie Fr\`ere, Maxim Libanov, Simon Mollet and Sergey Troitsky
hep-ph