There are two outfits with confusingly similar names that specialize in Rugers.
Their main product is heavy barrels or "tuners" to improve accuracy but they might be willing to make you a faux M14 looking barrel.
http://accuracyriflesystems3.homestead.com/
I had an ARS heavy barrel on my Mini and it improved accuracy a good deal. It did not look particularly kewl but it shot well.
http://www.accuracysystemsinc.com/index.php
These folks have a wider assortment of muzzle appliances.