This Lego T. rex and Stegosaurus by Sami Mustonen (senteosan) are about as accurate as you can get on a relatively small scale. You may be surprised to learn that both images are actually digital renders. I can only tell the difference because some of the bricks aren’t available in the colors used.
EDIT (AB): Like these? Both the T-Rex and Stegosaurus are on LEGO CUUSOO, where you can vote to have them made into official LEGO sets.