OH NO! I can't find my copy of Clone Brews! I bought it because it had three recipes for each brand of popular beer around the world. Once made by extracts (easiest), one with partial mash (harder) and one all grain (hardest). It had EVERY one I was looking for when I found it in a store. I'm sure Negra Modelo is in it.
Good luck on finding your book, Jim. Figured Negra would not be too difficult, but ya never know until you ask.

Most recipes/formulas in the food biz follow their own versions of your beer recipe description: easiest -flavor extracts to mime the flavor, harder - real product with some extenders for duplicable standardization, and hardest - real deal, only the raw ingredient & a lot of patience to get it right.