I considered going to a tractor powered splitter for a short moment, but decided that I did not want to stack hours onto a $30,000 tractor to run a log splitting cylinder when for $1,000 I can buy a Woods tow behind with it's own Kohler engine that is about a $300 throw away engine. And as far as sound, I run the Kohler at around half throttle and it is far less noisy than the Kubota engine.
A little tow behind 27 ton Woods splitter will out perform a tractor hydraulics driven one for sure, if you run your PTO to a stand alone splitter pump you can likely get tow behind performance, but to do that you are running the engine and hydraulics on a tractor with a finite life span and a cost in the multiple 10's of thousands of dollars... as in your spending a **** of a lot of money for a power source for that splitter while you could be running a dirt cheap and disposable little utility engine that costs pennies to buy and to maintain.... if you even bother to maintain it. They will run for many years of intermittent use with zero oil changes or maintenance. Ask my father in law... he does not believe in oil changes or maintenance on anything. Somehow he gets 100,000 to 150,000 miles from his Ford box trucks with only adding oil to them a few times a year. When the engines die, he has it replaced with a junk yard engine and goes at it again just adding oil now and again.