Doubt it's a Chromag. The headtube doesn't match their other frames. Also it's got very little seat post insertion length space. It has what looks like a custom tuned Vorsprung shock, Chromag works pretty close with SRAM.
Just looked at who posted the original photo, it's Pete from North Shore Billet. I would guess it's a personal project. Last clue it's not Chromag is that it doesn't use any of the little tabs n shock mounts that have been shown on the sly by a particular machinist that has been doing other proto work for Chromag.
Here come 2022 Santa Cruz bikes! Hightower gets a 145mm shock. Tallboy gets SRAM UDH and chain stay adjust is no longer an option
Hightower had 145mm of travel for a while, probably around 8 months. Just a longer shock stroke. I know a bunch of people who did this before it was a factory option.