Technically, the tool would simply be known as an
8mm Free Spinning Orbital Polisher
The 5" aspect would relate to the backing plate but that's not really a feature of the tool in the same way calling the Griot's Garage 6" Random Orbital Polisher the 6" has nothing to do with the polisher itself, it's the measurement of the backing plate that comes with the tool and for the record I've been asking Jeff Brown for about 3 years to either sell the tool without the 6" backing plate or repackage the box to read Griot's Garage 8mm Random Orbital Polisher and include a 5" backing plate.
My suggestion back then to Mercedes-Benz and also today is to build the Mercedes-Benz version of the Porter Cable random orbital polisher. I have a list of features it would offer.
I also have another suggestion for a tool from FLEX. Maybe there will be a chance for another meeting.
Me? Most of the time when I want to detail a car fast I use the FLEX 3401, in my experience it is the fastest way to buff out a car while producing professional quality results.
That said, there are times where the best tool for the job is not a powerful gear-driven orbital but the opposite, a simple tool with a free spinning 8mm orbit.