Modern paleontologists believe that most theropod dinosaurs had feathers and that modern birds have evolved from some of their smaller relatives.  We have been feathering our models since 1995 when evidence was found to indicate that Mononykus olecranus was feathered.  Since that time, with newer discoveries, the fossil evidence for feathered dinosaurs continues to mount.  Even though there hasn't been conclusive evidence that the larger theropods were feathered, I believe this is only a matter of time and soon T-rex will be reconstructed with a full body of downy feathers.  

Most of our life reconstructions are made by applying real feathers one at a time and laying them like roof shingles, starting at the tail and ending at the head.  We also do carved feathers in cases where sculptures can be touched by the public.