peruvian tallarin verde?
I too have been on this quest to find an authentic Tallarin Verde recipe.
All I've found so far is a link to someone who has 'reengineered' the sauce: http://www.discusscooking.com/forums/f21/peru-green-spaghetti-38023-2.html Look at the bottom of the page for the recipe.
EDIT - I found this explanation of the origins of pesto in Argentina and Peru: http://originalrecipes.com/node/183477 Great fusion - Genova supplies the sauce, China supplies the noodles.
EDIT - after reviewing a few more sites there is some implication that the (pesto) sauce could be made with huacatay (Peruvian black mint). No recipes found yet with this ingredient.