Yeh you are right on the Mamm Navajoa. My apologies for the wrong name on the turb it is actually T.hoferi . It does look very like a Strombo. Being a lumper I'd probably chuck strombo into Turbs. It seems to hybridize with some too. The closest turb as far as I know to strombocactus is actually T.alonsoi. That is a beautiful species. I have some hybrids I did with it and strombo. They are intermediate between the two.
Also sorry to have taken down some photos from an earlier post, my flickr account is full.