Ok, Trichocereus Frankie is an odd one. Despite being one of the most sought after genetics around, not much is known about the history of this particular plant. The most that is known, is that originally, Frankie was gifted to Rodni Chisar, a famous grower from Aus. Rodni then cloned and distributed him.
Frankie is quite hard to classify as he has traits that span a few Trichocereus genus. My best guess would be a weird peruvianus / pachanoi cross or possibly a peruviana / chiloensis cross.
Either way, this is one heck of a gorgeous plant. The spines and notchy are epic and I find myself just starring at him wondering what the hell he is.