I have found the stab proof vest also. The item looked exactly like a bulletproof vest but the description said that it only provides protection from stabbing/slashing attacks. Unfortunately this was during one of my very first DayZ SA sessions and didnt think it was anything special which is why I didnt bother to take precise screenshots. However I am almost certain that I am wearing the vest in the screenshot below. It looks alot like the Tactical vest from this angle. Someone that has that one equipped could do a comparison to confirm.
