An off road tourer is just a tourer you ride off road its not a new sub genre
I've ridden a Dawes Galaxy around the Cairngorms off road and I've toured a mtb. Many 80's and 90's mtb's have rack mounts in fact my new On-One 456 has rack mounts.
However some makers have tried to raise the stakes with 26" wheeled touring bikes such as Thorn Sherpa's/XTC's/Nomads, Dawes Sardar, Oribit Romany. Roberts and dave yates have also got similar bikes and there was someone called Caribou. Often these bikes have good tyre clearance, long wheelbases, multiple brazeons such as up to 5 bottle cage mounting points etc. In the past Giant and Scott really raised the stakes with URT full sus framed tourers where the specially made racks attached to the suspended portion of the frame, really smart and at the time expensive.
Knock yourself out Mikee but all your really doing is putting a rack on an mtb