Looks very, very nice, thanks for the tutorial.
Google tells me I can make this with one of my favourites,, beef shank, or goat
I need to source peppers which can be a bit of a challenge
Anyhow, I have bookmarked this
Both lamb and goat are the traditional meat, and I think beef became popular because of availability. because these are small batch tacos. Very rich and filling. Beef shanks will work for sure, or oxtail or beef cheeks. For making tacos (and not soup) you need meat that is fatty so that the consomé has the fats (oils) needed to fry the tortillas while keeping them moist, but with a a little crisp. I did a couple of cooks using only mozzarella as the filling to test the griddle temp (300°) and time before flipping (2 minutes+). Even these had a wonderful flavor. I can envision melting cheese and roasted jalapenos as a filling.