I don't know how to make it, but I do know where to get it around here. Mostly, that means local mom'n'pop Mexican restaurants.
Not much help, I know.
A few things I know is to make everything from scratch. Ground meat, pico the gallo, cheese, sour cream, jalapeno or habanero sauce depending on how hot you want it and refried beans if you absolutely must have them. I'm not overly thrilled by the beans, but it can be pretty good. And make sure to heat the taco shells.
Edit: Your mix sounds pretty good, by the way. The only thing I'd add to it would be sliced, pickled jalapenos/habaneros!